Reproduction steps:
1. Open customer's attached project in "PopulusRun.zip" (2.4 GB) (IMPORTANT read note 3)
2. Build the project for iOS
3. Deploy the project to a device with Metal support
4. Play the game

Unexpected behavior: at some point while playing the application crashes on BufferMetal::SetData

Reproducible with: 2020.1.6f1, 2021.1.0a10
Could not test with 2020.2 because the application crashes at main.mm (2020.2 stack trace in edits), 2018.4, 2019.4, because of errors in Unity

Devices tested:
Reproducible with:
VLNQA00310 iPad Pro 12.9 1st gen (iOS 13.4.1)
iPhone 8+ (iOS 12.0)
iPhone XR (iOS 13.4.1)
iPad Air 2 (iOS 11.0.3)
iPad 9.7 6th gen (iOS 14.0b7)

Not reproducible with:
iPhone 11 (iOS 13.7)
Apple TV 4th gen (tvOS 14)
iPhone SE 2nd gen (iOS 14.0.1)

Notes:
1. There is a video attached of the customer reproducing the issue in "IMG_2294.MOV". When I was testing this, the project crashed in a few seconds (I didn't have to play the game)
2. This issue is project specific
3. Project from 1303935 crashes 100% of the time

First few lines of the stack trace (full in edits (ignore 2020.2 stack trace)):
* thread #30, name = 'UnityGfxDeviceWorker', stop reason = EXC_BAD_ACCESS (code=1, address=0x18)
* frame #0: 0x000000010340d864 UnityFramework`BufferMetal::SetData(void const*, unsigned long, unsigned long) + 60
...