I recently discovered that current cartridges for this game are preset to version 1.2.1, which is the fastest and most stable patch of the game. If you have this newer cartridge but have updated to 1.4, you will need to select “Restore Factory Settings” under the formatting options in the Switch settings. You will lose any data not backed up to cloud saves. Do not download any DLC data. I haven’t tested yet, but I believe downloading this will revert the game back to 1.4, as this happened with my 1.0 cartridge when I tried it a year or two ago.

Make sure to turn auto-updates off as well!