Results from searches on my collection:
"deck:my deck" is:review rated:2 -is:learn - 634 cards selected
"deck:my deck" introduced:1 - 10 cards selected
"deck:my deck" is:review rated:2 -is:learn -introduced:1 - 10 cards selected
I would expect from the last search at least 624 cards selected: 634-10=624. But it swipes out almost all of the results.
Tested on 2.1.56 Qt6 on both Windows and MacOS.
EDIT I have even simpler example. My collection has over 18.5k cards.
introduced:1 - 34 cards selected. This works properly.
-introduced:1 - 27 cards selected. Way too few IMHO. At first glance it looks, like it selects cards, that were studied today, but introduced earlier. Which is not exactly reversal of the flag.