In one case, where the client was entering "NURSE" into the Occupation field, Support found that there were trailing spaces in the Occupation_Code table for the NURSE entry (and in the description text).  The following should remove those extra spaces so that the lookup works properly:
1.  Go to Occupation Code Entry (found under Codes in the frontend navigator)
2.  In the Find Code dialog box, enter %NURSE% and click Find.
3.  Once the NURSE record displays, if possible, retype the Description field value (eliminating any leading or trailing spaces)
4.  Switch screens to something else, such as Account Overview
5.  Go back to Name Entry and enter "NURSE" in the Occupation field. 

The description should display without error.