Still not fixed. There has been some communication on the EU side, I believe for consumer protection reasons, but no such protections in the US so they’re leaving us out to dry 
- EU thread: https://eu.forums.blizzard.com/en/wow/t/guild-bank-items-gone/
- Another (longer, 1700 posts +) US thread that has rough tallies of anyone who has reported issues: https://us.forums.blizzard.com/en/wow/t/guild-bank-missing-items-what-happened/
Latest info: