WebGL Player stops loading at 90% in Firefox when browser loses focus

Unity: Web Platform

2021.2.X

2023.1.X

2022.2.X

2021.3.X

2022.1.X

2020.3.X

Does not reproduce in latest 2020.3

How to reproduce:
1. Open the attached project "SimpleWebGLTest2.zip"
2. Build And Run the project for WebGL
3. Make Firefox lose focus

Expected results: WebGL Player starts
Actual results: WebGL Player stops loading at 90%

Reproducible with: 2021.2.0a1, 2021.2.16f1, 2022.1.0b12, 2022.2.0a8
Not reproducible with: 2019.4.37f1, 2020.3.31f1, 2021.1.28f1

Notes: Only reproducible on Firefox