The weird 2-3 shift

The 2-3 shift that everyone worries about; does that occur more under light acceleration or normal or hard acceleration? Any time I'm going down a hill and I've barely got my foot on the accelerator the RPMs in gear two might be 1500-1800, and then it wants to shift into third and the RPMs might increase by a thousand before dropping back down into third. It's almost like it wants to be at higher RPMs before shifting to third. It has never happened under "normal" or hard driving.