Bernard Purdie was asked to keep his mouth shut by Brian Epstein!!,..back in the 60's.
Ahhh,no.That never happened except in Purdies mind.Just listen to the drums on any Beatle song Ringo played on,and you can tell it's him.McCartney played on a few Beatle tunes,but,that's the ONLY other guy to lay down a drum track on ANY Beatle album.
When the Beatles recorded ,they mostly played a tune live,then added additional instruments/sound effects,so the drum tracks were never completely isolated,so these was bleed through to other tracks.
Steve B