I’m starting a new thread, even though this is probably related to what is discussed in this thread from just a year ago.
I was checking to see how the “Sync only documents in collection” option worked, and it seems to work more or less as expected.
However, if a previously synced document is removed from the collection, but the synced version is still in the sync folder, the next time sync is run, the removed doc gets moved to a “Trashed Files” subfolder in the sync folder.
This file does not appear in the Scrivener trash, nor is it picked up on subsequent syncs, and the binder location of the original item remains unchanged. However, two versions of the item will exist in the sync folders: one in “trashed files,” and one in its correct location (given appropriate sync settings.)