We have had several ArcGIS Pro projects hang since changing to ArcGIS Pro 2.3. Some were existing projects and others are new. By hanging, you cannot toggle layers off and on in the TOC, you cannot expand or contract the TOC, most of the tools are grayed out in the ribbon, if you right click on a feature in the TOC many items (Attribute Table, Properties, Symbology, etc.) in the popup are grayed out. You can still pan the map, zoom in and out, move items around your desktop. If you "Explore" a feature, the Identifying progress bar appears and never goes away. The only way to now exit ArcGIS Pro is from the Task Manager. If you click Cancel, the pop-up adds the words "Canceling..." and still never disappears.
The current project I was working on for a few days before it suddenly hung. Once this happens to a project, it persists each time you reopen the project and the project has to be recreated. Also when stuck on identifying, CPU usage for ArcGIS Pro is 12-20%, Memory 64-70% and GPU 2-5%. No errors are reported and it will stay like this until the session is exited from Task Manager.
Pro is not our primary GIS editor as we mainly use ArcGIS Desktop 10.6. We have been trying to utilize Pro on small projects to learn the application and test the platform. So far, 2.3 has been very unstable. We have not put a support ticket in as we only have one system with Pro installed and it is not our primary GIS editor.