This only happens to me since like 1-2 weeks to me.
Sometimes in game I'm unable to pick or change a weapon. So just now I looted a tresor with time buttons and right after i grabbed everything and reloaded (with weapon switch), I packed my gun away to run faster. Then I wanted to grab my gun but my player didn't take it. I tried serveral times. With pressing and holding q (different weapons) and right click (since normally the player takes its gun while start aiming). Welp, I died like 1 minute after, because I could not shoot. (maybe I die eighter way but nvm)

I sometimes had a similar problem, where I was unable to switch weapons, but I never could not take one. Also when the switching bug appeared, most times (or every time?) I could somehow change with q -> select weapon: while the animation for changing wasnt shown, after one shot the weapon changed.