I also work on Stockfish, that is not the reason. The reason is because the SF17.1 is functionally different, there is no way to get these to match without changing the net option to be the same as the stockfish binary.
See https://tests.stockfishchess.org/tests/view/69515c60572093c1... and https://github.com/lichess-org/lila/pull/18671
I don't work on Stockfish, but I can suggest using ShashChess instead. It is Stockfosh, but on top of that, it has been improved to capture the spirit of the human ingenuity and creativity.
Viren's been around a lot longer than I have, so I'd trust him instead ;) You can actually run the large net in Lichess (by selecting the larger engine in the dropdown) which would be dispositive.