I haven't been able to trigger it yet either (high approval; did all the same decisions for her quests that i have on previous patches).
Dunno if the issue is a bug, it's locked out atm, or we're both just missing something that's changed that we should be doing.
The patch notes do say they lowered her required approval for romance so I don't think it's intended to be locked out, and I have seen a few other people on reddit who are having issues triggering it, so I'm inclined to think it's a bug or bug adjacent.