The chip-based testing all autosomal tests rely upon is not perfect. False positives and false negatives are known to occur within these tests.? I don't remember off-hand how high this error rate is, but I do believe it is important to keep in mind. The SNP pack tests offered by FTDNA had similar issues,as it relied upon similar chip-based technology.?
According to the same principle as the example above, we could even imagine the hypothesis where an FF test would match one of a tester's PVs, provided that the position of this PV is covered by the chip (identical mutation or different from that sought initally by the chip).
Ewenn
