Missing backup?

I picked up a computer I hadn’t been using for three months to edit my Anki decks. First thing that happened when I launched Anki desktop was a sync (call this moment “A”). After editing I made a sync (call this moment “B”).

Unfortunately I made a mistake when editing and wanted to revert to the previous version but there was no backup between June and B - that is, no backup was made at (just after) A. Is that expected?

Can I revert to A by some other means? I mostly use Ankidroid.

Backups are made when you close your profile or the program. If you don’t have a suitable backup on your computer, perhaps you can locate one on your Android device.