I opened the egg with the internal pip. It was, indeed, an internal pip, but the chick was dead

Looks like it just broke the membrane and died before progressing any further. What could have caused this, so late in the game? I already have 4 hatched of this type and don’t need any more, so I’m not torn up over the loss, just curious. When I look up chicks dying after internal pip, I get explanations that don’t seem to fit in this case. Like, incorrect temperature or humidity, etc, but I know my readings were good and the hatch went very well otherwise, so it can’t be that...
@CluckNDoodle @Pyxis just out of curiosity, what do you think?
View attachment 2101841
I’m extra curious because this was one of the most active chicks during incubation. I even marked it with a smiley face (part of which you can see in the photo) so I’d know to grab that one when candling with the kids, because it was guaranteed to make back flips in there and be fun to watch...