I would suggest posting a brand new thread on the User Experience Expert Circle, buried in this Infinity '24 article it might not get the attention it deserves!
It would be good if you could post in that some screenshots of your advanced associations in that post. I suspect with will be in the “type” for using that Class Join where the duplication has occurred, though it could be the nature of the join condition itself (hard to tell without some of configuration)
You may also find this useful Utilising Advanced Associations (joins) with Insights in Explore Data to report on Tags