Music (on Mac) Playback stops after 14 seconds

Well I've tried the multiple libraries method multiple times and ways. Any time I sync with the cloud it just reverts to the old matched files that won't play -- even if they are deleted from one library, synced with cloud, then re-opened on a separate library (they always appear as 'matched' even if deleted).

The fix I have uncovered: downloading the files from cloud.

Since this is a legacy library that has moved between Macs and external drives, the current Mac/library didn't point to those local files that were matched to cloud years ago (which includes the trouble files). So whenever I encounter one of these trouble files I click the download arrow and it creates a duplicate file in the external hard drive that is now playable and the source file for the library. Unfortunately it does duplicate the file--so I'm deleting those old ones from the hard drive as I go through the process.

The good: retention of my library's metadata and the songs now play through without issue

The bad: tedious and time consuming to go through and do this for every corrupted/unplayable file in a huge library and duplication of the files

More context:

On mobile, I'm able to stream songs that do the stall out method described above. But there is a noticeable skip sound that occurs around 14-15 seconds. This leads me to believe it's an iTunes Match + Apple Music on Mac issue.

I'm contemplating re-importing my hard drive library files as a method to upload 'clean' songs to iTunes Match. However, I don't want to lose my 18 year history of personal music in my iTunes library data (Believe it or not I had a healthy iTunes library prior to 2006 and got upset when I lost all that metadata with a new Mac purchase. Ever since I've made sure to keep my library intact).

So I see two viable options:

1. Figure out what's causing the consolidate library error and hope that a clean library consolidation will solve the playback bug.
2. Or re-import the files but try to retain library metadata.

Any power users out there know how to do either option?

Thanks for the reply - this may be the fix I need.

For the two libraries, are they containing all the same files? Did you have different directories for both libraries? I wonder if deleting files from the streaming would delete them on my external drive (I would have a back up copy just in case). Trying to parse the steps you're describing.

It sounds like your iTunes Match sub applies to both libraries, correct? I was wondering if it would work with one account/sub and multiple libraries.

Fwiw I investigated the bit rate, file type and other characteristics of those older matched songs that don't play with those that do play and there is no rhyme or reason as to why they won't play (I.e., no common thread in characteristics).

I just tried opening an older iTunes library, deleting one of broken albums and updating cloud library. When I returned to my other library it had also deleted and synced with the cloud library. So I'm not following the steps properly it would seem.

I've toyed around with different libraries and have determined the iTunes Match files are definitely the culprit, but I'm still struggling with how best to remove/re-add them without blowing up my library's history and metadata.

Are you doing 'sync library' for both the stream/local libraries you describe?

I think my best fix is to make the library 'forget' these files and repoint them at the hard drive that has the files, or is there a way to redo iTunes Match?