Reproduction steps:
1. Open the attached "SerializationIssue.zip" project
2. Open the "DLLBugScene" scene
3. Build And Run with IL2CPP
4. Observe the Console in the Player view

Expected result: No errors were logged - serialization succeded
Actual result: A "MissingPropertyBagException" error was logged - serialization failed

Reproduced with: 0.6.0-preview (2020.3.36f1, 2021.3.6f1)
Could not test with: 0.6.0-preview (2022.1.8f1) (could not resolve build failure), 0.6.0-preview (2022.2.0b1, 2023.1.0a3) (could not resolve package errors)

Reproduced on: Windows 10, Windows 11

Package: Unity Runtime Scene Serialization

Error: "MissingPropertyBagException: No PropertyBag was found for Type=\[SerializationTest.TestEmptyClass]. Please make sure all types are declared ahead of time using \[GeneratePropertyBagAttribute], \[GeneratePropertyBagsForTypeAttribute] or \[GeneratePropertyBagsForTypesQualifiedWithAttribute]"

For context, the user is trying to use the Unity Runtime Scene Serialization package in Oculus Quest builds, and they're using a third-party API that uses DLLs. Even if the types are referenced in AOT settings, the DLL scripts fail to get serialized in build while the rest of the scene is working. The problem persists in a very simple DLL containing an almost empty class (Assets/ThirdParty). The user has tried using the RegisterPropertyBagRecursively without success (Assets/Serializer.cs). The "DLLScript" GameObject has a component from the DLL, and after removing this component, a new build successfully serializes the scene

Related forum thread: https://forum.unity.com/threads/runtime-scene-serialization-package-status.1168783/#post-8210691