Switching to a primary weapon that was just picked up while the player character is prone causes him to stand up, go prone again and then switch the weapon.
Follow the steps to reproduce this bug, it happens 100 % of the time and causes the player to emerge from behind cover, become visible and also become vulnerable for longer than needed.
Maybe related to issue #8675
http://feedback.arma3.com/view.php?id=8675
Place a single soldier that is equipped with a primary weapon and a sidearm on the map and preview the mission.
Go prone
Open inventory and drop primary weapon to the ground
Pick it up again
Press "Switch gun / handgun" button
Observe the player standing up, then go prone again and finally switch back to his main gun
DEV version
0.59.105679
Mass closing ancient tickets with no activity for > 12 months; assume fixed or too trivial.
If this issue is still relevant in current dev build, please re-post.