I load my game and I have no weapons, equipped or backpack. I went back through a dozen save files and all of them load with no weapons. Clearly I had weapons then, so ???
I got a save editor to look at the save files and I found all the weapons gone except fists. All weapons and grenades. The weird part is it is not just the last save. It went back several dozens of saves, both auto and quick. Whatever bug caused this, it is not writing weapons and grenades to the save file.
I reloaded the most recent save and I went into my stash. I found my weapons. Wow, that was close.