Lights go on when grandmaster is blacked out

Question: 

Why would my LED PAR fixtures light up when I use the blackout button on the ION.

This only does this when I have the ETC house wall dimmers set to a certain pre-set for the show - all house lights off, and I have a fader up with a scene using the LED PARs.

If the house lights on the wall panel are all on, and you use the blackout on the ION, then the LED PARS will fade out.

The DMX output will say 0 on the fixtures for intensity, but the color outputs will be up and the lights will stay lit?

Any Idea's,

Thanks!