It appears that sometimes (not always, average of maybe once every few hours of playing), a player character can be bugged where if he leans (in my case, leaning right) while crouched and aiming down sight, he will very quickly and completely lose his breath, as if he's been sprinting for quite some time.
Video: https://youtu.be/4FGw0cVf9qM
ADS while leaning right and wait a few seconds.
Notes:
-I verified that "Hold Breath" is not double-bound to my leaning keys.
-In the case in the video I was able to replicate it once before starting the recording while leaning right. I also tried to replicate it leaning left and failed, after which I could no longer replicate it leaning right.
-My buddy that I was playing with while recording experienced the same bug three times in a row a few minutes later, then couldn't reproduce the issue afterwards.