I get that message "Syncronizing 1 photo" all the time. When looking in Settings > Sync activity, there are some photos registered. I dont really understand why lightroom presents me these looong resourcepaths/-links and syncdetails because I cannot interptete them anyway. Well double click the first leads me to a webpage where the name of the photo is. So I go back and notice it is a photo I have not marked for sync in a folder not marked for sync. I cannot see in any of the collections marked for sync (they are only a few) that this photo is added.
For one of the photos in the list, there is not resource path. And I cannot see the whole name in the sync details. Nothing happens when I double click it. I do not know what do do wiht these photos.