I double-checked everything, even if the Boole> Hide new edges option might leave the edges there, but keep them hidden, etc.
My result so far is that any N-Gon with a hole in it would share that edge with itself.
It became clear to me while testing the Dissolve, trying to leave only one edge in the N-Gon.
N-Gons with a hole can’t share their own edge (except in earlier versions); I recorded this screen capture:
I hope that workaround (cutting two edges to begin with) helps, as my intuition tells me that this specific N-Gon/cut behavior will stay, but I leave the reports and see what happens.