Hang after unloading game level and async loading main menu scene in additive mode

There are no reproduction steps.

Reproducible with: 2021.3.8f1 (user)

Reproducible on: Windows 10 (user machine)

Note:

• The Dump file is attached in “TSU_hang.zip” file
• Changing SceneManager.LoadSceneAsync to SceneManager.LoadScene seems to fix the issue
• Testing by CQA is impossible due to inconsistent reproduction even on the user’s side

Notes on how the game handles scenes:

• There is always a main scene that is never unloaded, containing "ApplicationManager" and other high-level global objects
• The main menu is loaded in additive mode
• When the game is run, the main menu scene is unloaded and the game scene is loaded in additive mode (containing game-related menus, etc.)
• When a level is loaded inside the game, a world scene is loaded in additive mode and objects are added to that dynamically
• When exiting back to the main menu, first the world scene is unloaded, then the game scene is unloaded, and finally, the main menu scene is loaded (in additive mode)