Full-blood siblings & stepsiblings

My sims have 9 kids that are biologically both of theirs, but in all the profiles for the children (even after aging up to YA & teens) show both sibling and stepsibling in the relationship portion of their profiles. I was wondering if anyone else was having this issue. And if so, does it affect anything romantically? Because the last thing I need is for my Sim children to be romantically involved due to this weird bug😭