If you have indexed items in the Trash, it would appear only new items are being newly added. If you empty the Trash, technically you should see all the files re-added.
I never index except transiently as part of a smart rule to import from Dropbox
Those are not the duplicated files
It potentially sounds like a Dropbox issue.
Have you ever seen this behavior with data not being brought in from Dropbox?
It is never happening with the Dropbox data. My use of Dropbox indexing is a rarity for occasionally importing documents when I am at some remote computer. 99%+ of my DT3 documents are imported. I sync the databases through WebDav on a Synology.
I haven’t quite pinned down yet how to predictibly reproduce the problem - I just know that it started when I began moving Groups to a different database. When I figure it out beyond that I will let you know.