The issue with the bank as stated below is fixed in my game as of patch 1.03.
I did a search to see if anyone had found a possible cause before posting this and saw none.
First of all to everyone, backup your user settings to an external/thumb drive, your bank items are saved there on your system. Also, this is somewhat a long read, not sorry.
Yesterday, upon returning to Sanctuary, I found my bank empty, all 40-ish items gone. Thankfully I had most of it backed up on my thumb drive, only lost about 15 items, no problem will find them again. I submitted a ticket with 2k to inform them of what I was doing/did when it would occur as it happened 2 more times.
I retraced what I was doing and found that when I opened the Eridium sealed chest on Skywell-27 (Promethea), at the beginning on the right side of map, and then save/quit anywhere on this map, then continue game to reload, then go to Sanctuary my bank would be empty. If I open that chest and travel to another map then save/quit/reload, my bank did not empty at all. I also went to 5 other maps and opened Eridium sealed chests, save/quit/reload at each, then to bank, nothing missing. I did this over and over with and without mayhems, with my lost loot full and empty and my bank was not affected. I am still running around looking for more but it looks like, for me anyway that the Eridium sealed chest on Skywell is somehow causing my bank to empty only if I open it, save/quit/reload there. I have only been playing single player online. I tried all that I listed above while offline and my bank was not affected at all and that includes the eridium chest on Skywell. For me, It has something to do with the hotfixes being applied while online.
Here is the location of one of the eridium chests on Skywell-27 (purple waypoint)
I’m curious if anyone can verify this, just remember to backup user settings first.