Autoconvert HTML to Markdown not behaving as expected

Things I have tried

What I’m trying to do

With the Obsidian Editor option “Auto convert HTML” checked, I paste the following from the clipboard into note:

<span style="font-weight: bold;">Title</span>

I would expect the following text to be inserted into the note:

**Title**

But instead, the following is inserted, which does not appear to be HTML converted to markdown at all:

**<span style="font-weight: bold;">Title</span>**

This behaviour also exists in the sandbox. Is this a bug or what am I not understanding?