"set due date" has a weird effect on "cards" table

Hi. Thank you very much for your work.

I am a hardcore anki user since 2014 and use anki ⁨2.1.43. I switched to new scheduler which destroyed my way of using filtered decks to catch back little by little (putting them into a limited parent deck). I’m trying to change my practices and tested the function “set due date” but I find the effect weird.
It adds a “manual” review with 0 duration, that’s ok. But the side effect is to decrease mean duration which is not ok for statistics. What is stranger is that the manual review is not included in the number of reviews (still 10 here). Example (sorry for French language) :

Thank you for the report, I will fix this so it does not alter the average. The issue is only at display time, so you are not getting bad data in your collection.