Reply to X1 not turning FX units on/off

For some reason, my 2nd X1, controlling decks C and D, is not turning FX1/2 on or off when i press the button.

Ive gone into the controller assignment, re 'learned' it again - when its in learn mode it works fine, but as soon as i leave learn mode it doesn't work.

Any ideas or help would be appreciated

Thanks