I know it does not help to say it works as expected for me. And currently I have a different setup to yours. I suspect it could be a couple of reasons.
Win10 may behave different one quarter of 2019 to the next as it evolves
My working set up is slightly behind yours
Win10 home 2019:03 build 18362.535
I recently re-installed so at present I have exactly the same few files listed in both the tile and SumatraPDF frequently read and that works well
Windows keeps a different “recents” list to the internal SumatraPDF one so they can behave differently when files get moved / renamed, windows will not know if the file is invalid and tell SumatraPDF to look in the wrong location SumatraPDF can also be wrong in attempting to open files that have been moved/renamed by windows and one common cause is when web or cloud file references vary from a temporary cache. This potential sync difference may get worse as time goes on.
When you hover over the tile entry, windows will generally show the file path in addition to the file name, it may help to see if there are any differences there.
I have no reason to suspect it, but feel this is a problem outside of SumatraPDF, since as you say SumatraPDF is keeping a good/reasonable internal history of where those files were last found