Continue watching shows multiple instances of media when different versions exist

[theguymadmax]

Partially why I'm reformatting my libraries to have mutually exclusive HD and 4K libraries (i.e., the same movie does not exist in both).

Sorry to say, having separate libraries won't resolve the issue. I have a separate test library, and whenever I add a movie there that's already in another library, both versions always show up in the Continue Watching section.