"ObjectDisposedException" is thrown when adding elements to a Material's Invalid Keywords list in the Debug Inspector

Steps to reproduce:

1. Create a new 3D URP project
2. Go to Assets > Create > Material
3. Select the created Material and enable Debug mode in the Inspector (three dots at the top > Debug)
4. Add list items under "Valid Keywords" list by clicking "+"
5. Observe list items are created under "Invalid Keywords"
6. Delete the list item from the "Invalid Keywords" foldout by clicking "-"
7. Click the "+" under "Invalid Keywords" foldout
8. Observe the Inspector and Console

Actual results: "ObjectDisposedException: SerializedProperty m_InvalidKeywords.Array.data[2] has disappeared!" error is thrown and the list item field is gray

Expected results: No errors and the list item is created with a normal input field

Reproducible with versions: 6000.0.52f1, 6000.3.16f1, 6000.4.10f1, 6000.5.0b11, 6000.6.0a6

Not reproducible with versions: 6000.0.51f1 

Tested on (OS): macOS 26.5, Ubuntu 24.04

Notes:

• Can be inconsistent to reproduce sometimes and additional adding/removing elements is needed to reproduce
• Typing in the list item properties has a weird behavior too - inputted characters are written in the wrong element items. For example - entering anything in Element 0 field populates the last element field instead