Card-intervall decreased to "1" for a ton of (old) cards

I have recently come of a longer break (I know, don’t shame me) and found my deck to be acting very peculiar. When I started anki, everything seemed to be normal, I had about 1800 cards due, with 34 cards having an intervall of “1 day” (I know this, because I kept a backup before starting my review session).

After limiting the amount of cards per day to 200 (and my three lower decks to 66 each) I noticed something peculiar - now a ton of cards (323!) had an intervall set to 1 day, even though I know many of them quite well - one card had an intervall of 3 months! It is quite frustrating, having to go through cards many times, even though I know them well. What is even more peculiar is, that according to the faqs the due times for correct cards should be longer and not shorter!

Does anyone have an idea, what the cause for the rescheduling could be? It was my understanding, that limitng the amound of cards per day should have nothing to do with the intervall. Is there some sort of mechanism, which decreases the intervall if a card is to far behind schedule? If yes, can I disable it?

Any help is much appreciated!

Please follow the steps on When problems occur - Frequently Asked Questions. If problems persist, please select one of those cards in the Browse screen and view the Card Info screen to see the review history.

Thanks for the response!
I disabled a few extensions, downgraded to a earlier Anki Version and imported the older file. which seemed to help. After studying for a while I decided to synchronise. After that, about half of my cards (~3000) where reset to “new”, meaning I lost all my progress! I posted one of the card info screens:

After that I imported a older file, disabled the Anki 2.1 Scheduler and synched again - this time, no reset happend. I will now continue working without the Anki 2.1 Scheduler for the time being.

Any Ideas what could be causing this issue?

You’re using an old Anki version and add-ons, so it’s not clear where the problem lies. If you can reproduce the cards being reset in the latest Anki version with add-ons disabled, please provide the steps you’re taking to trigger the issue.

Update: I since updated Anki and now the problem does not occur anymore. I dont know what exactly caused it.