About three months ago I replaced the ballast on a ceiling fixture that has two circuline fluorescents - 32W and 40W. It's been fine up until now. Lately, the fixture has been acting strangely in that, occasionally, it takes a minute or so after I flip the switch before it comes on. Usually, it happens the first time it is switched on for the day, although occasionally it happens when I toggle it off and on.

Would this indicate a bad ballast? It is an Advance ballast from Home Depot, the second one. The first one was defective out of the box, and looked like it was installed by someone else and returned (bent wires). Is it a potential hazard?