The Item container of bank mess up sometimes, happends rarely though (Not sure about inventory container, didn't had issue with that)
I got regular bug reports of my script saying the bank has run out of pure essence, even though the bank is open en the pure essence is visible in the bank.
I debugged it and indeed the item container did not contain pure essence at that point.
It can be fixed if you reopen the bank.
Might something to look into
Hope this post helped you a bit
Khaleesi