crontab schedule on Alpine Linux runs on days it's not supposed to run on

I have a schedule in my personal crontab on an Alpine Linux 3.20 system that runs at 00:10 from Tuesdays to Sundays (i.e., all days of the week except Mondays):

10 0 * * 2-7  "$HOME/local/sbin/backup.sh" prune-daily

This appears to trigger on Mondays too. Why? --- Note that my initial report gave the symptoms as "Does not run on Sundays". I misremembered what happened, sorry. I have corrected the description of the symptoms after investigating them more thoroughly. The crontab schedule is correct, as it was from the start.