After scanning both devices also need to exchange and compare their respective lists of files including permissions, modification times and block hashes. As everything was created at the same time, these have all to be checked for conflicts. If they are the same, no conflict copy will be created, but it will still take some time to realize that.
Guess (!) about the laptop out of sync items: It might simply be slower than the desktop and still assume, that it needs all the files in the index from the desktop. Given time, it will figure out that they are equal and this list of files will vanish without all/any of them being synced. You can check whether anything is actually synced by looking at the “Latest Change” in the folder or by opening “Global Changes”/“Recent Changes”.
We had a discussion about the most efficient initial setup of lots of data, but I can’t find it anymore. I would assume that it was faster, if you first scanned only one device, then share the folder with the second device. Thus the second device will already have the index from the first device in place and can check for modifications while scanning.