Another GEDmatch query.
 

A new match has just appeared on my results, and this kit matches with both me and my 2nd cousin. However the match doesn't appear on our individual lists, and when I check the new kit number on it's own (one to many) it only brings up one match - someone who has no matches to either of us.

In addition in the field where it says the source of the DNA sample it says "synthetic". I have not come across this before and wonder if anyone knows what it means.

Thanks

I'm not sure but I came across this by googling:

Desktop tools
Borland Genetics Kevin Borland's free toolkit for reconstructing GedMatch-compatible synthetic DNA kits for deceased ancestors using raw DNA files of living relatives.

and this:
Lazarus is one of the Tier 1 utilities offered by GedMatch. It allows you to recreate at least some of an ancestor's genome, based on living relatives who have tested. It takes two sets of kits--one set consists of descendants of the ancestor whose DNA you're trying to recreate (Group 1); the second set consists of non-descendant relatives of that individual (Group 2).


So it looks as though "synthetic" means that it isn't from an actual DNA sample.