you know you can check amount of ammo left in mag just by glancing at your inventory?
+ the idea about Dayz was to TRY and limit HUD (inventory not included).

if you don't know the difference between a hack and an option setting that has been changed maybe you should reconsider posting stuff on a 'bug-feedbag' site. This is to report bugs not to whine about your problems with the game.

because regardless of which one you have in your hands, it only refills the first one that it encounters in your inventory (which is highest one up). you have to swap the empty with the full so the empty is at top of inventory and you can refill empty one. Probably loop bug in the code.

The problem with this is, that it only refills the bottle highest up in your inventory, regardless of which bottle you have hotkeyed and what hotkey you have selected.