As Colin said.. it was a problem with double spaces.  We used to have issues with " marks are not balanced in the Lookup filters, so to fix that I looked for double spaces in the filter and removed them. This seemed to help fix the " balance issue, but in this case changed the filter of part number XXXX  YY  to XXXXYY so now i have implemented my Baseball fix... Three spaces and you are out!  
 
Part numbers can have up to 2 spaces in it, but not 3.
 
I'll send the fix to Lynn later today as I am working on something else in the lookups and it is not ready to be sent out right now.