Loading a scene using "ResourceLoader.load_threaded_request" using (subthread = true) causes cascade of "Invalid Task ID" errors

[cosmoddd]

Tested versions

• Reproducible in the 4.3 beta2 build. Haven't tested earlier 4.3 builds. Not reproducible in 4.2 builds.

System information

Godot v4.3.beta2 - Windows 10.0.22631 - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 2060 (NVIDIA; 32.0.15.5612) - Intel(R) Core(TM) i7-8700K CPU @ 3.70GHz (12 Threads)

Issue description

When I use
ResourceLoader.load_threaded_request(level, "", true)
to load a level, it causes a cluster of the same error message:
wait_for_task_completion: Invalid Task ID

The more complex the load, the more these messages keep appearing.
This does not happen when I tweak the level loading code here:
ResourceLoader.load_threaded_request(level, "", false)
or here:
var loaded_scene = ResourceLoader.load(level)
This was not an issue in the latest 4.2 release.

Steps to reproduce

Import the project and open the "Base Level" scene.
Press F5 to start the game.
Notice the error outputs in the Debugger tab should all say:
wait_for_task_completion: Invalid Task ID

Minimal reproduction project (MRP)

The project can be downloaded here: https://drive.google.com/file/d/1EGhASSLeyHpbAaYk0Vv9C0yQLZhI2B8B/view?usp=sharing

It weights about 200 mb and is compatible with 4.3beta2

[dalexeev]

CC @RandomShaper

[akien-mga]

Haven't tested the project here yet, but for the record @RandomShaper, I've seen the same errors in W4's project genesis.

[matheusmdx]

Bisecting points to #93082 as the culprit: