Not saying I don't believe you, but this is a new one to me.
We must all aspire to better ourselves, to better our person and to better our quality; but no matter how much better we become, no single one of us will ever be better than all of us combined.
Yea I wouldn't know, I upgraded mine twice within the first couple days of early access and haven't tried again since. Haven't had any inventory bug issues.
I'm a little shy to try upgrading my bank as well. I don't know about this morning's maintenance; my bank bug happened last weekend.
I bought the first bank upgrade and deposited 1,000 gold. Afterwards I upgraded one of my characters' personal inventory slots to the first upgrade. Shortly after that I got a bunch of in game mail with all my Imperial Edition pets and treasure maps, for the second time. I had already claimed all my Imperial Edition bonuses on a different character, somewhat to my dismay in that he had low level CE Treasure Maps from the other alliances that would have been better claimed by alts.
So I thought the additional CE perks were odd and I went to the bank to see about putting these new pets away, only to find my bank upgrade was reset, the 1,000 gold and all the crafting ingredients choking up my bank space were gone. Fortunately all the crafting ingredients came back after a relog but, the upgrade and the gold never did.
I posted about losing stuff out of my bank the first week of release, this is happening but not consistently enough to be addressed, or even accepted, as an issue.
Yeah, I had this happen to me a couple of days ago. Logged in one evening to find all items in my bank gone, items and gold, and slots reset back to 60. When I logged another character and my items returned but not the gold and slots. Contacted support who said they where aware of the issue but no time stated on a fix.