Steps to repro:
1. open a new universal RP template
2. Add a new camera
3. set the new camera Display=display 3
4. set the new camera type=overlay
5. add the new camera to Main Camera > Stack
6. go to game view, check the output on display 1, display 2 and display 3

Expected: display 1 shows rendered scene with camera stacking, display 2 and display 3 show message "Display N. No Cameras Rendering."
Actual: display 3 does not show the message

Repro: 2019.3.15f1 + URP 7.3.1