I'm finding the same thing. There seems to be something I'm not considering regarding versioning. I would really like some comments on this issue because it's costing me hours of time to undo a mistake, which with any other versioning system should have taken less than a minute.

I edited the "live" version (fortunately in a Development site) but the site hadn't been touched for 6 months (and 8 days!!! - taking note of the limit on restores to 6 months).
The edit went wrong and I deleted a card by accident. Apparently it saves every 2 mins.
Now I have version 336 that is a dud (please don't ask why we have that many versions - it's not the issue) and I cannot delete it and start again from version 335. All the options are greyed out. Including for 334.
Is it because of the 6 month timeout or is it because the Power Apps release has changed?
I am guessing the solution is to change my workflow to immediately publish a new version every time I want to do an edit, then I will have a less than 6 month old, and current Power Apps release version to return to if my development version experiments go wrong.
Thanks in advance ...