Perusing DNA data from 23andMe for an adoptee who is related to me in a fashion as yet undetermined. He has a new match with another man who also matches to me. The adoptee's matched to this man include matches on 3 segments of the X chromosome. One of those three matches is a "half" identical match, which is what 23andMe reports when two people match on one copy of a particular chromosome. The other two matches are "complete,' which is supposed to mean that the people match on both copies of the chromosome (for example, my sibling and I have a bunch of "complete" matches in addition to a bunch of "half" matches; the complete matches are places where we both inherited the same chromosome material from both of our parents). They have no other "complete" matches.
Since men have only one copy of the X chromosome, I can't imagine how two men (regardless of their relationship) could possibly have any "complete" matches on the X chromosome. Any insights out there?