Unable to select Employee from LOV

Hello

We have recently upgraded from 12.06 to 12.1.3.

A client has been trying to update the Project Manager on a Project with a long standing Employee but in Self Service HTML screen they are unable to find this person using the Search function.  The Employee does not appear in the list of names to select from.

The Employee can be found using the search function in an Project Enquiry HTML  screen  Responsibility and also in Forms responsibility

Many Thanks

Jeanette