Reproduction steps:
1. Open the attached “BugRepro” project
2. Open the “Assets/Scenes/SampleScene.unity“ Scene
3. Enter the Play Mode
4. In the Game view, observe the blue circle. Note its size.
5. Exit the Play Mode
6. Select the “Particle System Sample” GameObject in the Hierarchy window
7. Open the Game view tab
8. Observe the Blue circle in the Game view

Expected result: The circle should have the same size as observed in Play Mode
Actual result: The circle is smaller than in Play Mode

Reproducible with: 2021.3.51f1, 6000.0.58f1, 6000.2.6f1, 6000.3.0b3, 6000.4.0a1

Reproducible on: Windows 11
Not reproducible on: No other environment tested