I would go there during the day, when it is out and check some stuff.
First make sure you are getting voltage out at the dish. I have had the occasional wire get a break in it, and when it gets hot, it pulls apart just enough to loose contact, but when it cools back down it touches again.
And while it is working, check your svt, see if it seems like it is out of alignment at all.
If i had to guess, I would not guess Tria, but thats mostly cause in the last few years of putting these things in, i can't remember ever seeing a tria act like that. Normally they either work, or they don't