I've seen somewhere in the code that you are preventing flying soldiers from kneeing and I think I've found a bug.
steps:
1. get on a mission with guys with fying suit
2. order the soldier to fly out the avenger
3:
a) use the elevate down button
b) order soldier to "walk" to the voxel directly below him, so that he stands on ground
4. hit the knee button
current result:
a) the soldier doesn't do anything.
b) the soldier knees for one state machine update loop and stands up without command ( after that he can kneel normally )
what I think is the expected result:
the soldier should end up on his knee.