Permenant Crouching some times when player uses 'e' (melee) it causes him to jump or crouch.
Pistol sound has no volume change over distance.
If you try to open a chest when another player does, the GUI to help you open it (Press 'X' to open) stays there.
Sometimes when I jump-melee I cruise along the ground with the one animation frame (of me mid air with sword above my head) but I don't actually hit, I just continue to glide along the ground as if I'm sliding.
In the defence mission on 'Despina' we smashed a window and we couldn't use the console (doors were locked and there was no option to 'Hack' the console but it did turn green) so we both suffocated and died.
On occasion sometimes after a console has been hacked it stays green (all of them on the map).
If Loki or Ash go invisible just before you get to the extraction and finish the other players can see him do a walking animation below them as the ship takes off. (Looks very silly).

Using my Snipetron or Latron on corpus does not register head-shots  Those guns usually rely on that tactic, so without the head-shots and gets quite frustrating. 
Starting a match as Loki and getting the personal goal as "Use Warframe Ability" none of Loki's powers register as a "Warframe ability" there for making that goal not completable. (apparently same with Mag)
Getting goals occasionally that are in-completable. i.e. not having proper ability attached.
Switch teleport within an elevator going up makes both players fall through.
We mess around allot when it gets to the end of the level. If Loki uses invisibility before extracting he has a walking animation instead of locking in place on the ship, also when I am playing with Loki as he does the same thing I also can see him doing a walking animation on my screen as well as my player locking to the ship. 
If loki uses switch teleport when he is in the extraction zone and I am not, it finishes the mission but Loki gets no rewards(credits) for that mission.
If volt overloads at the extraction point just before my team-mate enters i still complete my overload before locking onto ship.
Decoy positioning is still not accurate to where the player wishes it to go.