PC/Steam version here.
This bug is a little difficult to explain, and I don’t have the means to capture it on video. Should be easy to reproduce though.
If you have a team with a hero, whose active class is not among the first few in the selection, but further down the line (in my case Sunspear), the result of a kingdom or type search in the class menu will seemingly come back empty. If you move the empty screen to the left a bit, your search result will show up.
The problem is, that the screen position you were at is carried over into the filtered search, I think.