During the loading screen of the saved game, I accidentally pressed "F4" to activate the feedback screen while the game was loading, and at first, nothing happened and the loading continued normally.
However, after finally loading the saved game, it loaded with the feedback screen open along with the game screen simultaneously, creating overlapping screens and information, even making it difficult to read the feedback screen. Even so, the camera moved with the movement of the mouse, even though it was in the background, and when I closed the feedback screen with "ESC", the game froze and no command worked except the "F4" key to open the feedback screen again.
I couldn't even close the game or return to the menu screen; I had to close the game in the Windows task manager and reopen it.