Mailto link with a label loses its mailto prefix when rendering to CommonMark Markdown 1.2

When rendering the following xwiki/2.1 content to markdown/1.2 and parsing the result back:

[[x>>mailto:a@b.c]]

Expected: a mailto link to a@b.c with label x.
Actual: it's rendered as

[x](a@b.c)

and read back as a URL link to a@b.c.