Turning consecutive paragraphs into list items doesn't display the right number in the tinyMCE WYSIWYG editor

Use case:

• Create a document with several paragraphs.
• In the wysiwyg editor, click the "numbered list" button to turn a few consecutive paragraphs into list items.
• Instead of being numbered 1, 2, 3.., they all have the same number, 1.
• The correct number is printed after saving, when viewing or when reloading the editor.