New Incest Glitch

I created a family in which the parents of a girl broke up.  The wife married her girlfriend and the father is living there as a roomate.  The daughter’s name is Lynette and she is attempting to flirt with her biological father Brutus.  I read there were incest glitches in the past, so I’m wondering why this is happening in my game.  Are any of you still having this issue?  The weird thing is on the family tree it clearly show Brutus is Lynette’s dad.