[Update 16 May 2025]
After some contact with Microsoft, and a little bit of help, they unfortunately have become unresponsive. This hinders us in our efforts to prevent more users from experiencing data loss.
However, in the meantime we are not sitting still. But working hard, and making progress, on possible solution scenarios.
What has become clear is that after the update the files in the 'old' backup location may not be removed immediately. But after some time, they are and cannot be retrieved. This might give some users the opportunity to rescue their work.
So again, and as always is the case: Please be vigilant in copying your backup files to a safe location.
See the previous post for file location.
Thank you so much for your trust and patience.