My perfect IV Vaporeon seems to be lowering IVs?

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.

I found a perfect Eeevee that was unfortunately only level 4 at the time. However, it had 112 CP and 31 HP which seems to be the max values for the level 4.

Naturally I got excited, but decided to evolve it first because what were the chances I'd get the Vaporeon and moveset I wanted. Turns out, I did. Vaporeon with Aqua Tail. I was psyched!

However, I noticed that the more I power it up, the weaker it seems to be getting. It initially gained +43 CP per power up, and I notice it go down to +41.

It is now level 12 from its original level 4, so I checked the IVs again using the IV calculator and my 15-15-15 turned into a 14-15-15. I'm afraid of it only going lower so I stopped powering it up for now.

Any thoughts of what could be wrong? Is it because I didn't power up the Eevee first before evolution?

EDIT: I just double-checked and the IV spread seems to now be 15-15-13. Are these IV calculators just faulty? I'm using the silphroad one, for anyone curious.