Is my clutch pedal not returning because it's a (new) diaphragm clutch?

Vixen has the original style B&B pressure plate and Kitty has no problem pressing the clutch pedal. She enjoys driving Vixen around. I did put a diaphragm style pressure plate in my truck, because with a 12" B&B style pressure plate, it was a little difficult for Kitty. I want my vehicles to be easy for her to drive if she has to. That's more important than a "correct" pressure plate. There ARE decent diaphragm clutches on the market. It is true though that the B&B style is stronger. Always has been.