Inspector window becomes blank when adding or removing entries of a serialized Dictionary on a Prefab asset

How to reproduce:

1. Open the “IN-149355” project
2. In the Project tab, select the “UpgradeManager.prefab”
3. In the Inspector under “A) Dictionary directly on the MonoBehaviour”, expand “Direct Stats”
4. Under “Direct Stats”, click “+” button
5. Observe the result in the Inspector

Actual result: The Inspector tab becomes blank, as if the Prefab had been deselected
Expected result: The new entry is added and the Inspector keeps showing the components

Reproducible with: 6000.6.0a6, 6000.6.0b10, 6000.7.0a5
Could not test with: 6000.0.1f1, 6000.0.82f1, 6000.3.23f1, 6000.5.10f1, 6000.6.0a5 (serialized Dictionary field doesn't exist)

Reproducible on: Windows 11 Enterprise (25H2)
Not reproducible on: No other environments tested

Notes:

• Clicking the “-” button blanks the Inspector in the same way
• All Dictionary fields are affected, whether declared directly on the MonoBehaviour or inside a nested [Serializable] class
• On 6000.7.0a5 the Inspector no longer goes blank as a whole, instead exceptions are thrown in the Console, only the first click of a sequence is applied, and its result appears only after reselecting the Prefab. Individual Dictionary fields can still make a Dictionary blank
• Not reproducible when the same component is selected in the Hierarchy