Headings located inside list items or quotations are rendered incorrectly in CommonMark Markdown 1.2

When rendering to markdown/1.2, a heading located inside a list item or a quotation produces wrong Markdown:

• a heading in a list item (- # One in Markdown) is rendered as * }} followed by {{# One on its own line, so the heading moves out of the list item;
• a heading in a quotation loses its > prefix, so it moves out of the quotation.

Expected

The heading stays in its container, e.g. * # One and > # Title.