I have a personal Slicer 4.10 build with Win32 Console output. I noticed that when installing/uninstalling extensions, that using the restart button causes another Slicer process to be started. Then you will have multiple Slicer processes which start to increase CPU usage. This is not an issue for a regular Slicer build which doesn't have console output.

This is still reproducible with developer builds of Slicer-4.11 (that show a console window). Most likely Slicer process is not terminated because there is still a console window. Maybe closing the console window explicitly when restarting the application would solve the issue, but the impact is quite low, as normally (such as in official Slicer builds) no console window is shown in Windows.