Reproduction steps:
1. Open the attached project (SafariTest.zip (56.4 KB)).
2. Build it to WebGL.
3. Move WebGL files to a server (Tested with MAMP htdocs).
4. Start the server.
5. Connect an iOS device to a macOS machine with a cable.
- Make sure device uses at least iOS 11.
6. Make sure "Settings > Safari > Advanced > Web Inspector" is toggled on the iOS device.
7. Make sure "Safari > Preferences > Advanced > Show Develop menu in menu bar" is toggled on the macOS Safari browser.
8. Go to your server IP address with iOS device Safari browser (Tested with local IP shown in the macOS Network Preferences and 8888 port).
9. Go to "Develop > 'Device name' > Safari" and click the first selection.
10. Select the Console tab.
- Notice the errors.

Actual behavior:
- Loading never finishes.
- WebAssembly Unhandled Promise Rejection Error is shown.
- Check the screenshot below to see a more detailed error message.

Reproduced with:
2018.3.0a5, 2018.2.0f2
iPhone 7+ iOS 11.1.1

Notes:
- This issue might be a regression. 2018.1.9f1 doesn't show any errors, but loading doesn't finish either.