Reproduction steps:

# Open the attached “Repro“ project
# Open the “Assets/SceneB.unity“ Scene
# Replace all “StringContainer“ occurrences with “Container“ in the “Assets/SRBugDemonstrator.cs“ Script
# Open the “Assets/SceneA.unity“ Scene
# Select the “SRPrefabInstance“ GameObject
# Observe the “Managed Reference 1” inside the Inspector (Debug mode enabled)
# Replace all “Container“ occurrences back with “StringContainer“ in the “Assets/SRBugDemonstrator.cs“ Script
# Observe the “Managed Reference 1” inside the Inspector (Debug mode enabled)

Expected result: The reference is not null and references the old StringContainer
Actual result: The reference is still null and is not able to resolve the old reference

Reproducible with: 2021.3.37f1, 2022.3.30f1, 6000.0.3f1

Reproducible on: M1 MacOS 14.4.1
Not reproducible on: No other environment tested

Note: Closing and reopening the “SceneA.unity” Scene fixes the issue