Dynamic Lobby Role Select

So I've been able to do this before but things have changed unexpectedly. In Dynamic Role selection two people have been able to have mirrored roles (ie. I choose top/mid and an ally would choose mid/top). I had 4 people in lobby and two were autofill, other two were jg/mid and mid/jg. Couldn't queue up. When did this change. I HAVE done it before.