Definitely it's npc stealing for me. It puts rockets(and other ammo) in almost the same position as plasma nades few era's back... Why craft them, if you can farm them much more faster in much larger amounts with not much of a risk involved.
(And I still think that, if this kind of stealing was impossible, no cooldown bypass, and the mercs were bought naked, and there was no BOS vs. Unity encouter this era, then we wouldn't face the mutant swarm or rocket spam so often)