Maybe try duplicating the AutoCat tab and reinstall AutoCat to clear out any weirdness, then copy-paste-values-only from your old to new to quickly get your rules back.
Not sure what the error was. Went through the suggested steps in the docs and didn’t fix.
Went to the Tiller console and started a new spreadsheet. Created an AutoCat sheet there. Duplicated it to my original sheet. Copy and pasted the other rules into the “Copy of AutoCat” sheet. Deleted original autocat sheet. Renamed “Copy of…” to “AutoCat.” Ran AutoCat. It worked.