one very akward thing

Yes, I just posted something along these lines about a similar experience. What makes it more strange is the fact that when taking a gym with a friend the second person (as of last night) can't add a pokemon because "the gym is under attack". You would think that would not be the intended message in the case of same team members inputting into a recently downed gym.

I was fighting a 2 slotted gym yesterday and all the sudden its like wanna battle again? Random Dnite here now....

Well, the new system is still quite "new" so their might be one or more bugs around. But having a new Pokémon added while I was battling the gym to reduce prestige happend in the old system as well.

This is a really annoying thing...

I was attacking a gym and someone gave berries to all the defenders and added a few more mons...now, instead of a few fights, you multiply the new mons x4...

Maybe it's a bug, but they should really make it impossible to feed or add stuff once a battle starts.

I think the strategy now is find gyms that are your team, put mons in...

Attacking takes horrendously long now (unless motivation is at 0)...

If this bug is there, you can knock out 5 in a gym, and someone can put 5 more mons...endless.

i went hunting with a friend last night and i know once the gym is full and you are battling, you cant add pokemons if one dies. So this eliminates sniping gyms.

You can't. There were 2 guys attacking a Mystic gym (i'm mystic) and I couldn't add because it was under attack. I even saw the message "you can't put pokemon blablabla"..