here is some possible exculpatory evidence. i saw another flash in the first replay, shortly after the first flash.
first off, the first flash showed no units there in the lit area. and as i watched the replay unfold it did appear likely there were no units there.
however, second flash also showed no units, and i think there probably would have been units there... 3 seconds later when he moves down there, there's certainly peon traffic and a couple grunts. then again, the chopping peons are below where the map was in the lit frame, so they wouldnt be there, and the other grunts and peons seem to just be moving up and running at that time. so maybe not. i think this moves the meter more toward warvid glitch but still not sure