Web builds with Scenes containing a SubViewportContainer lead to "WebGL context lost" errors on iOS Devices

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Tested versions

• Reproducible in 4.3 stable and 4.4-dev*
• Tested on iPhones and iPads running iOS Version 17 and 18
• Behaves the same on all Browsers

System information

Godot v4.3.stable - Windows 10.0.22631 - GLES3 (Compatibility) - NVIDIA GeForce RTX 3060 (NVIDIA; 32.0.15.6094) - 13th Gen Intel(R) Core(TM) i7-13700K (24 Threads)

Issue description

Browsers on iOS Devices stop with a generic "OpenGL context lost" error when running a Web build with a SubViewportContainer in it.

Steps to reproduce

• open attached MRP or create a new Project containing a Scene with a SubViewportContainer
• build to Web
• open in any Broswer on iOS

Minimal reproduction project (MRP)

ios-wasm-bug.zip