When I go to the workshop of one of my games and select "Your workshop files => Subscribed items", I get many, many pages full of items, far more than I subscribed for.
Take Space Engineers 2 for example. I have subscribed to exactly four items, yet over 3700 show up as search results.

As a workaround, I have my four subscribed items favorited now, but it is really annoying that the search does not return what I specify.