Reproduction steps:
1. Open the project in "manual-certificate-bug.zip" and build for iOS
2. Deploy to an iOS device and inspect the debugger (you will see "NewBehaviourScript: DoHttpPost: Response: Status: OK Message: ok")
3. Close the Application
4. Using Safari on the device, go to https://www.digicert.com/digicert-root-certificates.htm
5. Click "Download DER/CRT" under "DigiCert Global Root CA" and press allow
6. Go to Settings -> Profile Downloaded and install the downloaded certificate
7. Go Settings -> General -> About -> Certificate Trust Settings and enable trust on "DigiCert Global Root CA"
8. Re-launch the Application using Xcode and inspect the debugger

Expected result: you will see "NewBehaviourScript: DoHttpPost: Response: Status: OK Message: ok" in debugger
Actual result: you will see "NewBehaviourScript: DoHttpPost: Exception:Type: System.Net.WebException..." in debugger (check note below)

Reproducible with: 2020.1.0f1, 2020.1.0a5, 2020.2.0a18
Not reproducible with: 2018.4.25f1, 2019.4.5f1, 2020.1.0a4

Devices tested:
iPhone 11 Pro Max (iOS 13.5.1)
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)

Notes: full debugger can be found in FullDebugger.txt