RobertRo101 - That video is excellent. I think it is a lot better for someone to visualise what’s going on.
So, if I understand correctly, it’s almost as if the Brew/HX priority mode button is completely dead, does nothing, and it’s stuck in HX mode, right?
I didn’t realise that it wasn’t the case until recently. I don’t understand the machine well as I don’t have one, but, it does seem it has developed a fault. I would check for disconnected wires on the switch and control box - but that was already suggested and you seem to have done it anyway.
Personally, I’d contact my retailer to say that the machine is not working as expected and let them deal with the problem.