Modifications to Mesh.triangles are not uploaded to the GPU when the Game view and Scene view window are open at the same time

Unity: Mesh

2023.2.X

2023.1.X

2022.3.X

2022.2.X

2022.1.X

2021.3.X

2022.1 has reached end of life so the issue will be fixed in a newer version.

How to reproduce:
1. Open the attached project "ProceduralGeneration.zip"
2. Enter Play Mode

Expected results: Mesh is generated
Actual results: Mesh is not generated

Reproducible with: 2021.3.8f1, 2022.1.13f1, 2022.2.0b4, 2023.1.0a5
Could not test with: 2020.3.38f1 (compilation errors in the Console window)

Reproducible on: Windows 10

No repro: MacOS

Workaround:

the mesh is correctly updated when scene view is not visible when entering playmode
- if Game View > Enter Play Mode is set to Maximized
- Or, if Scene View tab is hidden or closed
OR - no repro when MeshFilter.mesh is not used in OnDrawGizmos (instead can use MeshFilter.sharedMesh)