Reproduction steps:
1. Open the attached "repro_IN-83795" project
2. Open the "Assets/Samples/Cinemachine/2.10.1/Cinemachine Example Scenes/Scenes/Free Look character.unity" Scene
3. In the Game view overlay, make sure that the "Display 1" is selected
4. In the Hierarchy, select the "CM FreeLook1" GameObject
5. In the Inspector, in the bottom of the "CinemachineFreeLook" Component, press on the "Aim" dropdown
6. Notice that, in the Game view, the guide lines appear
7. In the Game view overlay, select "Display 2"
8. In the Hierarchy, select "MainCamera"
9. In the Inspector, in the bottom of the "Camera" Component, change the "Target Display" parameter to "Display 2"
10. In the Hierarchy, select the "CM FreeLook1" GameObject
11. In the Inspector, in the bottom of the "CinemachineFreeLook" Component, press on the "Aim" dropdown
12. Observe the Game view
Expected result: The guide lines appear
Actual result: The guide lines doesn't appear
Reproducible with: 2.8.2 (2022.1.0a15), 2.10.1 (2021.3.43f1, 2022.3.46f1, 6000.0.19f1)
Couldn't test with: 3.1.1 - Not able to find a way to execute the reproduction steps as the "CinemachineFreeLook" Component is deprecated
Reproducible on: Windows 11 (10.0.22631) (user's), Windows 10 (22H2)
Not reproducible on: No other environments tested
Note: After step 12, changing back to "Display 1" in the Game view causes the guide lines to appear even though there is no camera rendering to that display