The XB-70 suffered several "unstarts" at high Mach number and that was never quite solved.
All four inlet cones on the Convair B-58 Hustler were operated by analog electronics. Several suffered an unstart (at high Mach, of course, otherwise it's just a compressor stall) and when power was lost on one side, it would yaw into the unstarted engine, the vertical tail would snap off, and the aircraft would discentegrate in flight. I knew guys who refused to fly it fast except in wartime late in its career due to unstart issues. Most wound up out of the service and into an airline seat, mostly in DC-7's and B-707's.