I’ve seen people complaining about this in other forums too. it has repeatedly happened on 3 different xbox accounts several time. If you deposit an item that is DLC4 into the bank and then either log out or join another persons game, the items disappear and seems to revert back to what was in the bank before you deposited the items. It continues to happen even now. I personally started experiencing the issue about 48 hours after the DLC4 release. Some of the items i deposited on the day of release are still there, but beyond what was deposited on day 1 , everything else just disappears. Is there a fix for this? Is one being worked on? It is not an isolated issue. To add to this, it is only disappearing from the bank. If it is in the backpack, it stays.
EDIT: today I verified it is NOT only dl4 items. I had 3 One Shotter shields also disappear. These are base game items. The bank keeps rolling back to the contents it had on Friday after the patch. If i drop items out and then log out for awhile, those items go back into the bank, but also if items are deposited into the bank, they will disappear