Today I turned FSRS on with default settings. I don’t know it if it related, but I checked the stats to see the new graphs and I noticed the Future Due graph groups the bar with 20 million days when selecting “all” option.
My review history is from exactly 4,763 days… perhaps the issue is when there are +100K mature cards?
Btw, some background how I got these absourd intervals. These cards are from very easy flashcards from a deck which some cards were known for me but I wanted to keep the cards in my collection for searching purposes. I used a custom deck group setting to boost intervals when rating easy, so the review when the the card was in a multiyear interval lead to a next interval of a century.
If I reschedule all cards above 100 years this issue should disappear. I tried that. The issue is present with a highest interval of 24.8 years (mosty cards I started reviewing in 2013 with high ease).
I used prop:due filter in the browser. I realized there are 3 cards (from the same note) that appear to be bugged. The interval is just one day and the due says NaN-aN-aN but in the browser view there is 2091-12-21 which is impossible.
Exporting to apkg reset the cards as new. I deleted everything else from this backup. The issue is present with only three these notes in the collection. collection.anki2 - Google Drive
Thanks. This doesn’t look like an FSRS issue, but bad data in your collection. Those cards have a timestamp in seconds, but are marked as day learning cards, which should have a number in days.