Vanishing gear after patch

In the middle of a firefight in tundra express my game was logged out and pushed a patch. While that was all fine and dandy I was switching grenade mods and my rubberized stormfront vanished. It wasn’t modded, as I don’t play with anyone save my 6 yr old. I received it from the tmnt mission. Slightly perturbed as this has a low drop rate as it is, and I got it in my first run through. Is there anyway to avoid this in the future?