"Sara Mazrouei, a planetary scientist and educational developer at Humber Polytechnic, says that while we tend to think of a spherical shape when we hear the word moon, anything that orbits a planet, or another body in space that is not a sun, is considered a moon. "
By that definition nothing beats earth with all the satellites and space junk.
So, something is wrong (either the definition, the quote is missing "natural", or picking Saturn as extraordinary).
What's next, they'll discover an extra 256 as well in a few years?