Possible inconsistency with handling emphasis and strong when immediately followed by emphasis

[puopg]

When processing the MD string

***123****456*

<em>
  <strong>123</strong>
</em>
<em>456</em>

React markdown renders what seems to be some additional asterisks?

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and couldn’t find anything (or linked relevant results below)

Affected packages and versions

9.0.1

Link to runnable example

No response

Steps to reproduce

Compare the result of:

• https://spec.commonmark.org/dingus/?text=123456
• https://codesandbox.io/p/sandbox/sad-kilby-ggxhdp

This is just 1 word, where the first half is both italicized and bolded, the 2nd half is only italicized.

The MDAST that gets created from unified() => rehypeParse => rehypeRemark looks correct, so to me the issue seems to be either:

1. The syntax generated from the processing flow is incorrect.
2. The syntax is correct, and its React-Markdown's rendering of the syntax that is not correct.

Expected behavior

Actual behavior

Runtime

No response

Package manager

No response

OS

No response

Build and bundle tools

No response

[ChristianMurphy]

Thanks @puopg!

Tracing this further into the stack.
This is coming from the markdown parser react-markdown uses, micromark https://stackblitz.com/edit/stackblitz-starters-n2yquc

I know there is at least one emphasis related issue open micromark/micromark#92
But this feels different, would you be interested/able to post an issue to micromark @puopg?

[puopg]

Sure thing, lemme open one and ill link it here.

micromark/micromark#162

[wooorm]

Thanks, moving the discussion there :)