When you crouch while having the G17 equipped, you can’t stand up or move unless you unequip the gun.
In this image I am attempting to move/uncrouch while having the gun equipped, but it’s not working. I was only able to do any actions when I unequipped the G17.
This also seems to be the case with the AK-12. In this image I am also trying to move/uncrouch while having the gun equipped, but it isn’t working like the G17.