Can only set intensity, not on/off

[ibrewster]

I am having a weird issue with one of my lights: I can use siri to set it to any specified intensity other than 0% - including 100% - but I can't use siri to turn it on or off. Siri will happily accept the on/off command, and respond with "ok, the light is off" (or on, as appropriate), but the light does not actually turn on or off. Other lights with the same controller work fine, and controlling this light from my vera works fine, it's just this one that gives issues. Is this something that can be fixed?