How old is your Diablo? I bought mine in 2014 and it's still going strong and has never missed a beat.
Seriously, get in touch with Exposure and see what they say. I'm sure that a) if it's a known design flaw they'll tell you and b) they'll fix or replace your lights.
so i've heard, but i don't feel great relying on lights (3 units and two models) which have had the same failure mode. surprised if i'm the only one?