No, "memory hole" means the whole event was removed from the collective memory as if it never happened while it did, in fact, actually happen.
Basically a certain event happens but when it ends nobody talks about it, references it and behaves as if it never happened.
It has nothing to do with isekai and it comes from Orwell's most famous book.
I initially thought when I looked it up that you meant that the woman
specifically forgot she was pregnant, but I guess you were saying like figuratively everyone went on like her death never occurred huh.
I read 1984 when I was in Middle School outside of classwork and I think I stopped at the part where the protagonist got imprisoned so the memory is fuzzy.
In case you thought I was connecting the concept of a memory hole with isekai, I was more just mentioning the concept of a story having a very sudden, weird shift in tone, although I guess tbf past that point in my example it never exactly gets as messed up as that chapter but it does get a bit darker in dissonance with the harem actually going +1
Edit: Actually to add a trope I dislike: Throwing in some no-name or unimportant characters to get horrifically killed (the horrific nature is important) just to show how serious the situation is or "this is what happens if you fuck up". This is a bit of a hot take even in my mind because it
can be done well if it properly sets the tone, like I flip flop on this but Goblin Slayer does it right to some degree, there's an anime called Book of Bantorra that's kind of meh but opening with an almost immediate character death (regardless of how logical it was) sets the tone for the story being about an organization slowly losing members episode by episode. The issue is more when it doesn't set the tone at all for whatever reason. Maybe the author really wanted to put in a gruesome scene but didn't want to kill off any of the main characters for example.
