I would expect the intervals not to fall from ~ 5 years to 3 days, but rather stay a bit closer to the original interval.
I think the rescheduler is tricked by the reviews I did on 2022-04-17, which were done using a Filtered Deck with “Reschedule cards based on the reviews in this deck” toggled-off. Those reviews all have very short “intervals”, hence the 3 days “Good” interval after the reschedule.
At least that’s what I am guessing by looking at the card info. It seems that all the cards whose intervals drop drastically after the reschedule were last studied in a Filtered Deck with those settings. Also, they were all very mature before I deleted part of the review history.
Here is a sample of a note with 2 cards: Gofile - Free Unlimited File Sharing and Storage
Card 1 was not reviewed in a Filtered Deck with no scheduling; after I run the reschedule it keeps a long interval.
Card 2 was last reviewed in a Filtered Deck with such settings; after I run the reschedule the interval goes down to 3 days.
Both have very long intervals and most of their review history was deleted using the debug console.