Mewtwo ran away..

Something similar happened to me. It is just the RNG gods being unkind.

At least, your not the poor guy who had to explain to his girlfriend that the mewtwo he was helping to catch for her ran away.

Exactly same experience. At 34% catch chance per ball, the odds of not catching it in 11 balls is 1% (same odds as a critical catch). You are my brother/sister in RNG hell!

Yep. You're just very unlucky. Hope that doesn't happen next time.
I didn't throw as well as you did, I missed one and had some nice in there, and caught Mewtwo on my last ball (12, not only did we do color teams, but we owned the gym.) Thanked the guy who took it (well before the raid started), helped fend off challengers until the raid started.

If 100 people had your throws against Mewtwo, 99 of them would catch it. You're the unlucky one that didn't. Next time should be different, here's hoping it's soon.

Unlucky in the game, lucky in love

It is as hard as an Abra stays after not catching it the first time.

Could be worse:

https://pokemongo.gamepress.gg/q-a/how-do-you-tell-your-gf-her-mewtwo-ran-away

Sadly, this is a case of really bad luck I'm afraid. I've seen this happen to a few in my local Discord group as well. 10+ balls, all great/excellent curved throws with gold razz and the gold psychic medal catch boost, yet it still runs away.

We had one person who was miffed that his weather boosted 2844 Mewtwo ran on him today. It wasn't til a bit later when we figured out what the IVs are for a 2844 Mewtwo, and the mood went from miffed to crushed.

The pokegods are a cruel lot sometimes. =\

Not suprising because i've personally failed to catch tyranitar 2 out of 9 times.

The last two Ex-raids, the participants had a 100% capture raid. I tried myself on a friend's Account who couldn't attend. Very easy to throw at and first ball also. I was pleased to get some practice before next week. But I'm a bit on the edge of the seat because of reports like yours...

If each ball has a 34% chance at catching it then you would have a great chance with 11 balls but never a guarantee!
This is not a bug

After the revamp of Kyogre, I lost three in a row with 10+ balls and had a vast majority of excellent throws. Like you, it just meant I suck at RNG. Hopefully the game exists when you get a second chance to catch a mewtwo. I have not been so lucky, and hopefully I don't suck as bad on a fifty-fifty catch rate that you screwed up.