Invalid phone number

Lately I have been getting a lot of these messages - phone number carried from last year - cannot see anything wrong with the format…

Could you e-courier us the file that you are carrying forward from? We are having trouble recreating this.

~ Rob

It has happened to me few times intermittently on carry forward but does not stay on. Usually disappears after doing something in the file.

I get this message on pretty much every file. If I tab out of the cell the message goes away.

I’m not trying to be contrary, but we have never received this kind of message. What would make this message show for some users and not for others?