Family tree extra lines.

I have a large family save with 7 children all by the same two parents.  When looking at any of the siblings three horizontal lines connect them all. When looking at the parents it shows normal with one horizontal line connecting.  Same three lines for that sibling set when looking at generation number 3.  I’ve been working on this save for a while and want this error fixed. Please help 💛

I do not use any mods or CC.