Sorry, I don't know how I had missed this. I am glad to here you are having better results with 2019. We use an SMB file server . We try and limit each file to two admin users, one person on the project team and then our IT manager - just incase. We are switching this team to 2020 in hopes of seeing better results.
We are having issues where users can't see others updates to the project file. We have been using project sharing since 2016 and although there have been issues this seems to be a new one. It happens if people are working on our server or if they are working with a project file that is hosted on Dropbox. Recreating the project file from the most complete working file remedies the problem for a short period of time but the issue always resurfaces. Has anyone else had this issue in Vectorworks 2018 SP6?