Disclaimer: I play in online co-op with a friend.

1) sometimes at the beginning of battles, his character starts rushing in the middle of enemies, triggering opportunities attacks from them.
The issue there is that he does not click on anything at the beginning of his turn.
Erratic behaviour was observed three times so far in our game.

2) I created a very tall character just to try.
The issue here is that his head is not displayed in character sheet as it is hidden by the case where I can assign an helmet. Pretty annoying.

3) Elf robe in character creation is blinking sometimes.

4) Having to kill any guard in Fort Joy after escape (I did not see anyone giving the alert) when I decided to go back in to buy skillbooks and sell other things.

5) I never manager to join my friend's lobby. "Connecting" forever.
So we play the other way, he joins in few seconds.
Don't know why.