I had the same problem. It comes with Qt VS Tools 3.3.0 added recently. The solution, as mention above is to:

• disable automated update for Qt VS Tools extension
• uninstall Qt VS Tools 3.3.0 version
• install Qt VS Tools 3.2.0 version from https://download.qt.io/official_releases/vsaddin/
• restart VS and recompile -> it will work