I'm not sure how long this bug has been around, as I found an issue on feedback tracker similar to this from 5-6 months ago but it was never resolved. http://feedback.arma3.com/view.php?id=9243
I've also made sure to disable all my addons and verify my game cache.
The bug does not seem to occur when your unit is holding his primary weapon or rocket launcher - only when the handgun is equipped.
There also seems to be a bug that I can't seem to consistently reproduce after breaking out of the frozen animation in which you will be able to infinitely heal yourself over and over without consuming any First Aid Kits as long as you have one in your inventory.
UPDATE: As of the latest update, it still occurs in the latest dev build (1.09.113491); however, it does not occur in the main branch.
UPDATE 2: As of the latest dev branch updates, this problem is now fixed! Thanks!