Your response exceeds the limit

User gets error "Your response exceeds the limit. Try shortening some of your answers" is there any way to determine which answer is too long? Any sort of error log that I could gleam information from.

We have been through responses and checked for leading/trailing whitespace.  Exported box contents to word and done a character count. Copy and pasted into notepad to try and reveal any hidden characters. All to no avail.  Form is completed every month and out of 40 or so people only this one specific user has this issue.