How to reproduce:
1. Open the attached project ("1331091.zip")
2. Open "SimpleScripts.cs" in Assets/Editor
3. Notice how there are two fields "Budgets" and "BudgetDetails", one is of the "BudgetSettings" class and the other is of the "BudgetDetails" class
4. Notice how "BudgetSettings" inherits "BudgetDetails" and there is a "SomeList" field with NonReorderable attribute in the "BudgetDetails" class
5. Open "SimpleScripts.asset" in Assets/ScriptableObjects and look at the Inspector window
6. Expand Budgets/Element 0/Some List and set its size to something more than 0
7. Repeat 6th step with Budgets_details

Expected result: The "Some List" List is non-reorderable on both "Budgets" and "BudgetDetails"
Actual result: The "Some List" List is non-reorderable on "BudgetDetails" and reorderable on "Budgets", which means it ignores the NonReorderable attribute

Reproducible with: 2020.3.6f1, 2021.1.5f1, 2021.2.0a15
Couldn't test with: 2018.4.34f1, 2019.4.25f1 (the NonReorderable attribute is not supported)