I also had a recurring corruption issue using a Windows Server file share.

Before MacOS 27, I was always able to remove the Time Machine destination, replace the corrupted sparse bundle with a fresh empty one, and reconfigure that as the new TM destination. I even made a script for this, so I didn’t have to figure out the terminal commands every time.

Unfortunately the script doesn’t work anymore; it throws ‘error 25’ on my MacOS 27.

What’s weirdest is that, before the corruption, TM backup and restore used to work fine on my MacOS 27. Seemingly the backup functionality works as normal, but setting the TM destination was broken.