An odd one for @support, and after a quick search I can’t find the same issue, only similar!
Example of what I see, in Artist: Lorde in the Tidal Singles section there is a remix of Green Light (Chromeo Remix). When I add this to my library all three of the Green Light versions disappear from the singles section.
I know that I could select all three and add them if I wanted but even then only one is identified as duplicate so it’s strange that this happens in the singles section when adding thew one that isn’t duplicate!