Light Bulb or Ballast Problem?

I have a new 600w dimmable ballast dimming a used 600w bulb down to 250w for some seedlings I'm starting. I was checking on the seedlings and when I turned around for a minute and turned back around to the tent the light was out. The light stayed out for a couple minutes but then came back on.

Is it more likely to be a bulb issue or a ballast issue? Is there any way to check? The ballast is new and the bulb is used(i wasn't tracking usage properly at the time so I'd say either 1 or 2 grows were done on the bulb)

Obviously I'm not going to sit there staring at my tent for hours waiting for it to happen again, so I worry that if it's the ballast it could always be happening when i'm not looking.

Running a 600w bulb at 250w is going to cause the bulb to die fast. Most manufacturers say use the right wattage bulb when dimming the ballast, most sellers don't tell people this but with my ballasts they all said this. Also if you ever boost it you are supposed to let the bulb fire up and then click it to boost, I found not doing this blew bulbs within days or weeks.
Anyway, doesn't really answer your question but I would imagine its the combo of 600w bulb with only 250w running into it.
Really pisses me off that this info is not passed on by the sellers.
One of my ballasts said on it.. 600w/660w = 600w bulb. . 400w/250w = 400w bulb. So the dim down to 250w with a 600w bulb is too much difference from what the bulb should be running at.
You might find both bulb and ballast are ok as long as they are ran at the correct Wattage.

lol long story short chances are its your bulb.

Not an expert here, but I don't think that "dimming your ballast" means "dimming your bulb", but rather dim your ballast to work with a lower wattage bulb. Circumstances may vary and probably kill your bulb faster, or alter its light spectrum

Yeah i think it was a beat bulb, when i got home from work that day i saw it go out and back on again so i swapped it out. It was a pretty blackened bulb inside so i think it might b a bulb ive run more than i thought like 3 times. Prolly the fact of it being used up pretty good and lowered wattage didn't work too well together.