I am having an issue with the NUMWEEK Function that returns me week 3 instead of week 2 (according to google) for the following dates 13/1/2021 and 12/1/2021.
Unfortunately, it looks like Airtable does not support ISO for week numbering. You may want to request this as a feature request by emailing support@airtable.com. However, you can probably incorporate ISO week numbering into your system by writing your own custom JavaScript.
