Lightroom Constantly pulling wrong spart previews for cloud based galleries

My issue is very frustating. I like to have an LRC catalog for every year.  Each year I stop the sync of the old one and sync the new one.  I understand that shared collections from the previous year will be downloaded from the cloud into the "From Lightroom" collection set in LRC and are also available in the cloud ecosystem. 

My issue is that some of the smart previews from collection "Wedding A" will randomly start appearing in "Event C".  For example. Wedding a file A1234's preview will appear in event C replacing C4321's image. clicking on the info icon shows that the metadata is still that for C4321 but the image that it shows is A1234.  It's not just one or two images and not just one or two collections but it happens in multiple places.

When this first happened to me last year I contacted adobe and I got weeks of techs remote logging in to my account and creating new catalongs and uploading tests and deleting my sync data etc. Trying to recreate the issue.  I even had to wipe out all of my sync data and upload everything from scratch across multiple catalogs.  I couldn't keep up with the schedule of being home to answer calls and let them log in and take notes and send files to themselves for research.  I never heard back with further details and a few days later I got an alert saying the case was closed.  I've added scren shots showing the problem.

To be clear this only happens with collections from the previous catalog.  All current collections sync fine and don't have any issues.

Any help or ideas on how to repair this would be greatly appreciated.  (This has happened nomatter where the catalog lives and on multiple machines.  The errors are present in LR, LRWeb, as well as the from LR collection in LRC.

<mod> Multiple LrC Catalogs alternated in syncing is likely a culprit here - moving to Lightroom Classic