Albums in my library are not found via search

[HndrdFlwrsBloom]

This issue is present both on my up-to-date iphone 7 and macbook air. Both are connected to my premium spotify subscription. I am in the US. 

Hi all,

I am an avid music listener, and prefer to listen to originals rather than remasters whenever possible. In my library I have the 1999 and 2015 editions of David Bowie's Hunky Dory. These are the two that I could find when searching for the album a year or so ago. I was trying to figure which version I preferred, and searched for the album on Spotify to see if perhaps another version was now available. To my surprise I found only the 2015 version available through search. I then checked the artist page, and found only the 2015 version again. I booted my computer up and checked on Spotify there, found the same issue. 

I'd like to know what's going on here, and if there are albums that would be available to me that I cannot find via conventional search methods. 

Thank you very much.