The problem has been fixed. Airtable support emailed me to advise they’ve applied the fix and I’ve just tested it with success.  They said to first refresh the browser and if that doesn’t work to clear the cache. Refreshing the browser worked for me.

I’ve been using shift + enter and holding enter key on an empty row to mass create rows. It’s not ideal but faster than adding a single row at a time.

I have the same issue. Please fix airtable.