Yesterday I had a crash, and noticed that newly equipped gear vanished after logging back in again. I had equipped some new items gained from the previous mission, and then attempted to play a Bunker Buster mission, which crashed the game (Known issue from what I have seen posted here). After I logged back in, the slots that I had replaced items in were all empty.
I brought several items from the vendor, then attempted to play the BB mission again (As it was known to cause crashes) and the items once again vanished leaving me with empty slots. I was able to replicate this issue several times last night, and thought this may be relevant to the issue of vanishing gear in some cases.
For some reason, I was unable to access these forums at the time and was unable to report this whilst the BB mission bug still existed and from what I understand, the issue of BB missions crashing the game has now been resolved.
I am not currently aware of any other issues that cause the game to crash in the same manner and am unable to confirm if these issues were purely related to the BB mission crashes, or just a result of game crashes in general.