If the NCM data is to be believed, somewhere around October 2020, Stockfish dev hit +370 elo vs. Stockfish 7, but has since regressed to only +360. What's going on?
Only thing I can think of is a statistical fluctuation, which is plausible since the error bars are +/- 5. However, the gap between the October ratings and the current ones appear to be too large to fully attribute to statistics. This is especially the case if we believe Stockfish improved between October and December (which it presumably must have since engines are constantly improving). On the other hand, if the October versions of Stockfish are truly stronger than the latest ones, the newer versions ought not to have been accepted.