@sorata got it right.
The following screenshot explains the problem better. The supposedly “new” cards have revlogs and these revlogs are also being used by FSRS.
I have shared an apkg with just 8 cards on the Google Form that reproduces this problem.
Edit:
Having just this card in the entire collection also reproduces the problem:
Edit 2:
This single “new” card is also being used for optimizing the parameters.
Sorry, I can’t share the screen recording here. But, if you delete all cards in the shared apkg except this card, replace the parameters by 0,0,0… and then click Optimize, you would see that new parameters are being generated, using just this single “new” card.
@dae, if possible, I think video files (like mp4, webm, etc.) should also be added to the list of allowed extensions in this forum. If there is a concern about users uploading large files, a limit of file size may be applied. For example, the screen recording that I was trying to share was just 243 KB.