Reproduction steps:
1. Open the attached project “ReproProject”
2. Ensure only one Game View Window is docked
3. Enter Play Mode
4. In Game View, Observe the GUI shows a “Ratio” of 1
5. Exit the Play Mode and dock another Game View Window so that it's visible
6. Repeat step 3
7. Observe the value “Ratio” displayed

Expected result: The value of Ratio is 1 (i.e. WaitForEndOfFrame runs once per frame)
Actual result: The value of Ratio depends on the number of docked Game Views (i.e. WaitForEndOfFrame runs once per visible GameView)

Reproducible with: 2021.3.36f1, 2022.3.21f1, 2023.2.14f1, 2023.3.0b10

Reproducible on: Windows 11 23H2 (Play Mode in Editor), macOS 14.3.1 23D60 Darwin 23.3.0 (user’s)
Not reproducible on: No other environment tested

Note: Not Reproducible on Standalone build and Android Platform