How to reproduce:
1. Open attached "SkyboxRepro" project
2. Make sure that Texture Quality in Quality Settings is set to "Half Res"
3. Build and launch player

Expected result - Application is launched and skybox is shown
Actual result - Crash occurs

Regression introduced in - 2020.1.0a1
Reproducible with - 2020.1.0a12, 2020.1.0a1
Not reproducible with - 2019.3.0b9, 2019.3.0a12

Note:
1. Crash also happens on Android platform
2. Crash occurs with DirectX11, DirectX12, Vulkan, OpenGLCore, OpenGLES3
3. Did not reproduce the crash when Texture Quality is set to Full Res

========== OUTPUTTING STACK TRACE ==================
0x00007FFC9A6560CE (UnityPlayer) UnityMain
0x00007FFC992F8B3E (UnityPlayer) UnityMain
0x00007FFC993DFF89 (UnityPlayer) UnityMain
0x00007FFC993E5E9C (UnityPlayer) UnityMain
0x00007FFC993E0637 (UnityPlayer) UnityMain
0x00007FFC993E212F (UnityPlayer) UnityMain
0x00007FFC993E6CD3 (UnityPlayer) UnityMain
0x00007FFC99732DBD (UnityPlayer) UnityMain
0x00007FFD1F777BD4 (KERNEL32) BaseThreadInitThunk
0x00007FFD2044CED1 (ntdll) RtlUserThreadStart
========== END OF STACKTRACE ===========