The bug has been reported on Fallout 76’s subreddit. Players post that upon dying near an NPC, that non-playable character seizes their weapon and all ammunition associated with it and subsequently uses it in battle. These weapons can’t be reclaimed at the moment, and Bethesda is currently investigating the issue.
“We are actively investigating everything outlined in this thread, as well as other reports we’ve received here, on our own forums, or through support tickets,” Bethesda said. “In our next hotfix, we are planning to include a fix for the issue where NPCs can occasionally take a player’s weapon when they die. The remaining issues mentioned in [the] thread are all still active investigations, and we want to resolve them as soon as possible.