Nested ordered lists not auto‑formatting after upgrade to Drupal 11.3.2

Problem/Motivation

After migrating the website from Drupal 10 to Drupal 11.3.2, the automatic formatting of nested ordered lists in the CKEditor no longer behaves as expected.
Specifically, when creating nested lists using the Tab key, the numbering style does not automatically change (e.g., from numeric → alphabetic → roman numerals).
This behavior worked correctly in Drupal 11.2.8 and earlier versions, where nested indentation automatically adjusted the numbering style.

Steps to reproduce

Navigate to any content type using CKEditor (e.g., Basic Page).
Add an ordered list:
1. Item one
2. Item two

Place the cursor on “Item two” and press Tab to create a nested list.
Continue adding nested list items.

Observed result:
The nested list continues using the same numeric format (1, 2, 3) instead of switching to alphabetic or roman numerals.

Expected result:
Nested lists should automatically switch formatting (e.g., 1 → a → i), as demonstrated in:

CKEditor demo: https://ckeditor.com/ckeditor-5/demo/feature-rich/

Proposed resolution

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet