There is currently a bug exposed when two profiles are merged wherein the names and surnames are identical except that one profile's are written in all upper case.
All too often, the upper case one "wins". When one then enters the Resolve Conflicting Data mode to fix it, one finds that the "losing" column contains the mixed-case surname(s) but not the given name(s). Hence, one cannot simply select the (no longer existent) mixed-case given name(s). Instead, one must resolve the surnames, then edit the profile to over-type the given names in mixed case.