The '<Unknown>' in the heading has been inserted by GenoPro (this is OK), but then at the start of the next line, where normally the first names of the couple are reported, there is nothing. This is the same whichever spouse's name is blank. This line should begin with either 'They' or 'Father & <Unknown>'.
ps I am unable to find where this part of the report is generated - if it is in Dictionary.xml it is not obvious.