Leader of a Big Family Glitch

Try this

1 and 2 are the same level. 1 has a little more exp than 2, adds 2 as jr. 1 idles and 2 passes 1's exp (but not level), adds 1 as jr., back and forth.

Or just have two people of the same level continuously add eachother.

OR maybe it happens if two people try to add eachother at the same time (both have the conformation bubble up) and confirm together.

I've tried this on two of my characters who were at the same level. One was at 65%, the other at 16%. I tried adding the one at 16% as a Junior to the 65%. Doesn't let me.