I’ve been using Anki for some years. Until now, all my decks worked like this:
If you don’t add new cards, the number of due cards decreases over time.
Monday: 60 due cards
Tuesday: 55 due cards
Wednesday: 50 due cards
But recently, a deck where I haven’t added any cards for months has started to increase the number of due cards.
Monday: 50 due cards
Tuesday: 60 due cards
Wednesday: 65 due cards
And still increasing…
The Future Due stats are broken too. For example, after today’s review, the stats show:
Tomorrow: 31 cards
In 2 days: 58 cards
In 3 days: 57 cards
In 4 days: 49 cards
That looks normal.
But tomorrow there will actually be more than 31 cards to review.
I know due cards can increase from, say, 31 to 58 on the first review days, but over time they should decrease, not keep increasing like this.
I tried reset New cards/day, Maximum reviews/day but no use
That accounts for higher scheduled workloads on some days. When Anki tries not to schedule those cards on Mondays and Fridays, they have to go somewhere.
I haven’t been able to find a deck like that in your collection. The only deck that matches your description is “English (MAIN)” and you have been introducing New cards in it, for at least the past 10d (in blue).
You also have a pretty high rate of lapses (in orange), and a lot of Young cards (in light green). All of those factors combine to increase your workload in the short-term.