A normal blackout accounts for the initial blackout followed by the repeat.
All the rest sound wierd, but I think it's on your end. I'd check your stick- make sure it's calibrated and not spiking. And I think it could be something graphics card related. A driver problem or something. I had that happen to me, and I couldn't fix it until I re-did my drivers. I've also had blackouts start from the center going out, instead of from the edges inward, and I've had blackouts start as vertical "stripes" that started from the inside and spread outward. Impossible to fight, since as soon as the blackout starts it blocks the center of the screen...
At the very least I'd look at your stick, and maybe do a defrag. If the problem persists I'd look at a graphics driver or contact HTC.
MtnMan