Hello everyone!
The problem is following: 
Weapons in the Outpost and Bandit camp do not contain ammo.
I can't find how to fix it... I don't have any plugins that affect vending machines.

Fixed in last StackSize update

I am also having the same problem, but updating stacksize controller has not solved it for me.

My Stack Size Controller is also up to date and players are still reporting that problem.
Maybe another plugin is interfering with it too?