Same thing here with a burlap sack instead of a compass, but it definetely was not the last item I used or picked up (could have been the first in my backpack, but I'm not sure about that).

Do you still have this issue? Because I simply can't jump carrying two guns (talking about big ones, not pistols).

Well, I like the idea with the rope, but you should not have to attach it to the backpack, attaching the rope to the gun should make you able to put it on your back the way you can do it right now. Same goes for large melee weapons, you could attach a rope to it and put it on your back. Since it's so easy right now to get ropes (or improvised ones at least), I think it would be nice, if you would have to work for the comfort of wearing weapons on your back.

issue still occurs in .57
lost a shotgun and a makarov (outside of buildings)