I'm not sure what your sequences mean there, almost every boostback and re-entry burn has used three engines (they always light the center engine first, then th

I'm not sure what your sequences mean there, almost every boostback and re-entry burn has used three engines (they always light the center engine first, then the outer two). Most recent droneship landings recently have used three engines for the 'middle' part of the burn, shutting down the other two before actually landing. The recent GovSat launch tested a three engine burn all the way down (the first time they have tried that, AFAIK). There was nothing unusual about the number of relights. My guess is the issue was with the difficulty of the relights.