This is my assumption too. People are going to put stuff in the banks, and if they just restore everything where they were, that would override the stuff that was recently put in. Queue the next uproar.
I’m ok with stuff being returned via the mail. It’s a lot of work, but it lets us use the bank in the meantime.
I’ll do my best to get it updated either today or tomorrow. I’m in the process of transferring my terabytes of random digihoarding to a new system. 
My guild is just me and my alts on KT. I’m happy now that I cleared a tab out for TWW, but even with the assurance that the bug itself was fixed I was leery to use it. I finally had to this last week and everything seems still there. So there’s one win, I guess.
Still sad seeing the rest of the tabs completely empty. Can anyone else really give an accurate inventory list? I could more likely say yes that was what was in that spot after seeing the icons vs recalling from memory. I’m just hoping the items just show up in their old lil spots instead of mail. But who am I kidding, I’d just be happy to get it back.
having same issue 2 weeks now GB empty all tabs no recent log activity. And no INFO from blizzard }
Sentinels realm, Katt here, Drakkthar is my alt. post is from Katt Fromtheshadows guild.
And it’s still empty…
My personal Guild Banks have been fine (AFAIK) but my main’s raiding Guild (The DMZ, Eonar, EU) has had their bank (appear?) emptied for at least a couple of weeks. Nothing in the logs beyond the 26 July (and those were deposits). Even the Officer tab, to which only 4 of us have access, is empty of all last season’s raiding consumables.
People have posited it was since cross-realm or cross-faction, but one-person banks (who may or may not have alts from other factions/realms) have had this issue. Quite a few are older Guilds (ours has been around since at least early BC). As others have said, it is just more noticeable if 1 person has access, or a couple.
Guild banks still empty, missing thousands of items.
Just adding my name and guild to those impacted by this bug.
My guild bank is missing all items from all tabs! Had an issue accessing it just before the new expansion went live but let it go thinking it was just a glitch.
Went back to look and all was goon. Support pointed me to this location for bug reports.
Afraid to put anything in the guild bank for fear it will disappear.
There are also people that avoid the forums. if they see that a bug is known they just wait it out.
Imagine you are not online, so after 30 days it goes poof?
Every single tab in our bank was wiped. Every tab was in use and some were full. Old pets, consumes, you name it.
Myself and my co-gm have tested numerous characters and permissions and the entire bank still appears to be empty as of today.
Eludin-Aegwynn (US)
GM of Maledict-Aegwynn (US)
They’ve told us previously they can see the items that are missing but they have not stated anything about how or when the items can be restored. I just hope we get some information soon. Specifically - I want to know if it’s safe to continue to use guild bank and war banks and the restoration will be coming.
I’d love to know how many tickets have been created for this. It’s a good bet that the number is a LOT higher than the number of replies in this thread.
When they restored things for the Warband bank they put them in the bank for me.
My guess is they will put stuff in the bank (hopefully on the tab it was on) if there is room. Then any overflow will probably be sent in the mail. Just my guess.
Our guild bank is also affected. I’ve waited to ticket and locked access, but a reply on what we should do would be nice. Raiding starts in 2 days, and all old mats are gone.
Stuff from the AH or from another player lasts 30 days in the mailbox, stuff from Blizzard is usually 300+ days. You should be good for the better part of a year.
I don’t know if Felranys reads the U.S. forums but I too, would like to thank that CM for providing acknowledgement and some information as allowed. It’s too bad that no one in the U.S. forums were willing or most likely ALLOWED to post answers. And thank you Strappinlad for taking the time to bring that over here for us.
And I too, would like to thank everyone who’s hung in there, all trying to help, advise, encourage, commiserate, and verify that it’s actually a wider issue than any of us would have known without information from each other. While what’s going on is really frustrating, being here with others with the same issue has made me less alone in this, and that has helped. I mean, I’m sure ALL of us would have liked to have had regular Blizzard updates and advise here on the U.S. forums from when it started, but they are clearly unwilling to put in that amount of customer service.
LOL even as an account starting much later in the alphabet, I would be very happy if they did this. Because at least something would be visually happening, and some people would be getting their stuff back right away. I can wait, I just want it back, and a show of good faith would go a long way after the shoddy way this was handled from the beginning.
I have a bit more hope after reading the latest blue comments in the EU forums, although I’m also scared that hope is going to be dashed by an eventual “we just can’t fix it, sorry, it’s all gone. Here’s a compensation that really doesn’t even make a drop in the bucket compared to the millions and memories you just lost.” 
However. I would think that if what I think I remember someone saying much earlier is true: that they can actually see what’s invisible to us in our banks from their side, this problem should be able to be fixed with full return of all items lost, even if it’s mailing each individual stack directly. Time consuming as heck, but doable.