A guy on the rolexforums reported similar issues in 2019 or 2020. His 5711 developed recurring brown spots like rust on both sides of the bracelet exactly where the pins are covered up with metal on the non-removable links. In the end he got a new watch f...
Didn’t mention it but am guessing it must have been - either that or they put the movement into an entirely new case … it really does look absolutely brand new !