I haven't heard of this problem with the Ultra but some units of the old Arc AAA had a circuit bug that made the oscillator occasionally fail to start up. The failure was pretty intermittent and so the light would usually start within a few tries, sort of like an old car in cold weather. Arc LLC replaced those lights under warranty before they went out of business. I don't know if the current incarnation of Arc is doing anything about those old lights. My own semi-EDC Arc AAA has the problem but the failures are so rare that I don't let them bother me.

In your situation I'd just contact Gerber for a warranty repair.