What's all the yelling about? This "Yaw" effect is real, even in real aircraft, so that I heard.

It is overstressing the aircraft, meaning it starts to wander, or "shake". I have an uncle who was a Colonel with the U.S. AirForce, and he flew one of thos American supersonic bombers (can't recall the name, but looks like a MiG a little, but much, much bigger) and he too says there are limits as to speeds, before it starts to "shake" uncontrollably when going beyond its limits, or in altitude wise (air gets thinner allowing faster speeds).

So, to reckon, I believe this is a feature indicating overstressing or overspeed with the jet, try to ease your fuel back and fly normal at high altitudes...it does not shake to me, but does when using full afterburner and keeping it there until speeds get incredibly high....starts to "shake" a little too.