Yeah - that's not the case with me and from what I've read, others having similar issue are experiencing it as I described. That is, when it happens, it's usually out of the blue and disrupts all applications and goes until it stops.
My last post however, for whatever reason, while it's flickering, if I "right click" on the menu bar (just anywhere, I do it right in center top), it stops in a couple seconds. Sometimes it drags the window around in doing so but it at least stops.
That's right - a right click seems to interrupt it and rather quickly. So, my sometimes full minute is only a few seconds now.
Eric