Ok, that “could” be a myth busted, but I am not certain I would trust an immediate source that had a vested interest in the contents of said test.
I googled “olive oil refrigerator test” and got lots of results from credible looking sources saying it’s a myth, or at best unreliable. I chose the article at the California Olive Ranch site because California Olive Ranch was mentioned several times upthread as a maker of high quality EVOO.