With a single monitor the bug occurs to me exactly as described above.
By connecting an external monitor and configuring TwinView, the issue gets much worse: after open or save a file, or other operation, the screen goes black, flashes, flickers. Sometimes User Interface closes and returns to the login screen. Sometimes the system apparently recovers and returns to work, for a while. Sometimes system hangs and must turn off computer.
With a single monitor the bug occurs to me exactly as described above.
By connecting an external monitor and configuring TwinView, the issue gets much worse: after open or save a file, or other operation, the screen goes black, flashes, flickers. Sometimes User Interface closes and returns to the login screen. Sometimes the system apparently recovers and returns to work, for a while. Sometimes system hangs and must turn off computer.