Makes you question DNA evidence. If they had initially identified this child on the basis of DNA and then changed their minds, the whole process must be doubted. Clearly some measure of interpretation is involved in DNA identification.
I'm no where near a DNA expert. But it may be that they did something like an initial 12 marker test. With a 12 marker test you can get tons of matches. But if you upgrade it to a 37 marker you get closer and closer in your ability to make a positive identification of a relationship.---No interpretation, just more tests to narrow things down.