I wanted to let you know that I followed your suggestion and I’ve found the involved reviews using DB Browser for SQLite 3.13.1.
I feel confident that I found the right cells, and can say so because they were all done in immediate succession, with only a microsecond between each review (as seen from the selected cells in blue), there are 2,595 in total (bottom left corner), and because they have 0 duration each (red box on the right).
Also, using an Epoch to human-readable date converter tool I confirmed that its timestamp seems to match the date in question.
However, the reviews value is 0 in the type column (and not 1 as you pointed out). In your opinion, is it reasonable to change those values to 5 and see what happens?
From what I could see in this commit and in the Anki source ReviewKind enum 0 is precisely equivalent to a card in the LEARNING phase, which coincides with what is shown in my first screenshots.
I have updated all my devices and I don’t want any more conflicts between versions.
I would obviously do a backup with my app closed before pushing any changes, I just don’t want to mess things up any further before making a bulk change.
EDIT: added a proper image description.