The “688” class boats and Royal Navy subs did so on a regular basis. This was the main reason behind the Shkval invention! The “688’s” several times sneaked up on a Soviet SSBM, within 5,000 meters and pinged the boomer. Then add insult to injury the “688” would escape without being detected.

Even the Russian improved Akula managed to Tail & Track the US boomer in mid 95 in its bastion territory , Which proves that inspite of all the bugging of Ocean Floor , Either side could sneak in to each others territory and track their boomers.

As for the SOSUS being hype remember this, during the Cuban Missile crisis the Soviet Navy sent four SSK’s to Cuba. Three of the subs were forced to the surface.

I think you are talking foxtrot here , Even then the foxtrot managed to play hide and seek game with all the US ASW assets trying to track Soviet subs in the region , There is a book to the same effect which says similar thing. which said that they would manage to hide from Multiple P-3’s and surface ASW unit.

It also explained why Soviet subs could sneak up on a carrier and in a crisis they couldn’t find a carrier!

It happened once or twice not a matter of routine, Even during NATO exercise the Oscar managed to tail the Kitty hawk without she knowing about it.

There is so many know instances of Russian/Soviet coming so close , I am equally sure that there would be many unknown incident , The West Bragged about it and so it was known and hyped the Soviets didnt .