My understanding is that the usage you’re describing consists of typing multiple tags at once in the Tags Filter pane search.
Is this understanding correct?
If so, the issue is not about “year:1970” not being recognised, because it is:
The issue is that it does not work by entering multiple tag names at once It works by finding and clicking on one tag at a time.
So you can quickly find what you’re looking for by typing it in the Tags Filter too, without having to sift through a long list.