error message - cite while you write - 'the selection does not start in a field'

I have 2 records for the same author - one inserts fine but the other comes up with this message ‘the selection does not start in a field’ and I don’t understand what it means.  The author field is correct !!  Help !!!

Did anyone ever have any solution / suggestions about this error? One of my users is reporting the same problem and there doesn’t seem to be anything relevant in the FAQ