Still happening to me, kinda slightly different sequence but the end result is the same:
Undetected Rex is sad 
Tiny red dot shows where it’s clicking… It seems to go into Duel World mode when it can’t see Bakura at the gate but doesn’t actually hit the back button first. If it clicked the gate button to the left a little it might fix itself, same as the network issue I’m having.
Hopefully exams are going / went well 
