Yup, that’s why I feel it should either be removed or suggested that she knew something was up with her lineage but didn’t know exactly what.
I’d stick to the latter because otherwise the line, “Rey, never be afraid of who you are” doesn’t make much sense, because as far as she is aware Rey is nobody.
Or, you could throw the lineage junk out the window, and just have Leia know she is dealing with that inner darkness. Everybody’s got it. You don’t have to be the descendant of a bad guy to have the potential for evil.
Heck, maybe Leia could have also saw that vision of her on the throne. It doesn’t have to be because she’s a Palpatine.