A-12s were retired permanently in 1968 and the surviving YF-12 in the late 70s, and both only ever used the AFICS.
The dozen SR-71s equipped with DAFICS had much more stable inlets and weren't anywhere near as prone to unstarts. The inlet doors could be 'fine tuned' in flight by the pilot, but on the occasions when it did happen the system would actually unstart the 'other' engine by pushing the spike back out in order to arrest the yaw.
At cruise the speed would typically drop from ~M3.2 to around 2.8 during an unstart event and the aircraft could lose >10,000ft. The pilot would have to reset the inlets and climb back to speed and altitude. Not fun if over or near contested airspace!
I've been told by a former SR-71 driver that every jet was different and had its own little inlet idiosyncracies, but you generally flew with the same 2 or 3 jets on an operational 'Det' in Japan or the UK and got to know them well.