Double (quadruple) binding causes CTD

I have a joystick button mapped to decrease propeller pitch (and four of them). If I bind it to “decrease propeller pitch” only, on a twin engine aircraft, the right lever would move more than the left one (similar to pressing Ctrl+F2). However, if I bind the key to all four together, it cause CTD whenever I press it. Does anyone have a similar experience? Or is anyone able to find out how to let both prop levers decrease at the same time? And again, this only applies to decrease propeller pitch, while increasing them in sync works well with a single command.