SharePoint ASCX file manual deployment gives "Could not load file or assembly '$SharePoint.Project.AssemblyFullName$' or one of its dependencies" error

If ypou deploy ASCX file manually (by coping file and it's dll to CAG then SharePoint will give an error. When you deply with VS it should change this tag to a rela assemply name. Workaround for manual deployment is to change the tag by hand.

https://babasharepoint.blogspot.ch/2015/05/could-not-load-file-or-assembly.html