when carrying a wounded player in an MP server (any, without mods) there's a high percentage of cases where if the picker-upper moves away before the animation is complete for the victim, the latter is left stuck in place, hovering in mid air
this cannot be solved by the victim by any means other than respawn, ruining tactical gameplay. another "solution" is to kill the unit that picked him up, which causes the animation to revert and releases the wounded soldier.
players who are aware of this will seek to avoid carrying others (instead, drag) whenever possible, and use extreme caution when doing so as to try and prevent the bug from setting in