Delete all layer instead of deleting just one instance (PROBLEM !)

There's a problem, met many times from te last update.

In Room editor I pick an instance, Press delete.
95% - the instance deletes
5% - deletes WHOLE INSTANCE LAYER !!!

mostly it can be reverted by using UNDOcommand, but this time - not.
I have to re-made all the level.

What can I do to fix that?
Are there any backups of several last project saves ?


IDE 2023.11.1.129
Runtime 2023.11.1.160