I’m sure you know the story of the gra with his pidyon haben who went around to all the people who claimed to be kohanim since they were all only safek until he met one family with a shtar.
Do you have a source?
Even if true, it could be l’chumra.
Even if he held it was a safek, we clearly don’t pasken that way, as we are satisfied with one, and we say a brachah.