I concur, me and two mates confirm to have this issue as well, both on my custom mission and on Scruffy & NeoArmageddon's co10_Escape dedicated mission.
Since it happens in vanilla Arma 3's inventory handling, without any mission-specific scripts involved, I doubt either me or other mission editors are responsible.
I happen to have it recorded on video, but it's somewhere inside the six hours recorded yesterday, and it seems to occur commonly enough that the video is probably unnecessary.
Personally, as a developer myself, I have a suspect it's somehow related to the two new EventHandlers added regarding magazine (un)loaded, but that is just speculation on my part.