The AVR did cut out while running 3.1. I must point out that the AVR sits in a cabinet and it does not have a lot of room on the sides for ventilation, maybe 15mm each side. It has about 200mm of clearance at the back, 500mm clearance on top and the front cabinet door was left open and the AVR still cut out.
Does anyone know whether the AVR cutting out is caused purely by overheating, drawing too much current or a combination of both?