Dropbox selective sync enabled, still syncs 2800 files when compiling

I use Dropbox to have an instant backup of any code I write, and I'm the only one using it, but I'm having this problem, when I save a file in my editor Visual Studio Code and switch back to Unity, it starts to sync 2800 files. It doesn't take very long, but since I compile the whole time, Dropbox is constantly syncing.

I have selective sync setup like this, and I have a hard time figuring out what Dropbox is actually syncing. When I click the Dropbox icon and show "latest files", it only shows the file I changed, but apparently it's syncing something else.

Anyone has a clue on how to fix this, without turning of Dropbox? Are there maybe some hidden files that are being synced?

Thanks!