Reproduction steps:
1. Open customer's attached project in "New Unity Project.zip"
2. Make sure your iOS device has an internet connection
3. Build for iOS and deploy the application to a device using Xcode
4. Inspect the Xcode console and the application

Expected result: In the application socket status is "SocketConnected" and there will be no errors in the console
Actual result: In the application socket status is "ConnectingSocket" and there are "NotSupportedException: linked away" errors in the console (read note)

Reproducible with: 2019.4.7f1, 2020.2.0a3, 2020.2.0a20
Not reproducible with: 2020.2.0a2
Could not test with: 2018.4, because references in Scene get removed

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 12.1)
Not reproducible with:
Oneplus A500 Android 10 (Oxygen 10), Snapdragon 835, Adreno 540
VLNQA00012, Samsung Galaxy S6 (SM-G920F), Android 7.0, CPU: Exynos 7 Octa 7420, GPU: Mali-T760
VLNQA00122, Samsung Galaxy S9 (SM-G960F), Android 9, CPU: Exynos 9 Series 9810, GPU: Mali-G72
VLNQA00125, Google Pixel 2 (Pixel 2), Android 8.1.0, CPU: Snapdragon 835 MSM8998, GPU: Adreno (TM) 540

Note: full console log attached in console.rtf