Replace Data - duplicate entry for Profile fields if field is of type selection and has no value

Hi,
I have the Profile module enabled and I have a field of type "selection". For some users, that field has no value.
If, I choose "Update Existing Users" -> "Profile" -> "Replace Data" I get SQL duplicate entry errors for that users, like this

user warning: Duplicate entry 'x-x' for key 1 query: INSERT INTO profile_values (fid,uid,value) VALUES(x,x,x) in .../user_import/supported/profile.inc on line 78.

After a quick look at the the table and the code I think the issue is related to the fact that if the field in the user interface has no value, in the db it has value "0" and in the code there are some check against '', empy(), FALSE values that probably fail for the well known and complicated PHP empty value handing. Could you enforce that checks to avoid this bug?