Which package?

@formatjs/cli-lib@6.1.3
Tested with @formatjs/cli-lib@6.2.0 too and issues is still there

Describe the bug

We have a message that looks like this which contains 2 plural rules and each makes use of the # hash placeholder to have the plural value as part of the message

<FormattedMessage
  id="reproduction.example"
  defaultMessage="{topicCount, plural, one {# topic} other {# topics}} and {noteCount, plural, one {# note} other {# notes}}"
  description="Show when manager has completed all items for the upcoming 1-1"
  values={{
    topicCount: 1,
    noteCount: 4,
  }}
/>

When flatten is disable, we get the correct message
Here is the extracted message

"reproduction.example": {
  "description": "Show when manager has completed all items for the upcoming 1-1",
  "message": "{topicCount, plural, one {# topic} other {# topics}} and {noteCount, plural, one {# note} other {# notes}}"
}

And this is what is rendered on the page

When flateen is enable, the message is incorrect
Here is the extracted message. Note that the extracted message became plural rules nested within plural rules

"reproduction.example": {
  "description": "Show when manager has completed all items for the upcoming 1-1",
  "message": "{topicCount,plural,one{{noteCount,plural,one{# topic and # note} other{# topic and # notes}}} other{{noteCount,plural,one{# topics and # note} other{# topics and # notes}}}}"
}

And this is what is rendered on the page for that message. It looks like because in the extracted message, as hash placedholer is being used, # ended up using the value of noteCount as we have plural rule nested in another one

For your reference, this is how we are using @formatjs/cli-lib. This is a small portion of the code that we have as we don't want to share everything for security reasons but should be enough.

import { extract } from "@formatjs/cli-lib"

const files = await glob("{src,pages}/**/*.ts*", {
  ignore: ["**/*.d.ts", "**/*.{spec,test}.tsx"],
})
const extracted = await extract(files, {
  format: "smartling",
  flatten: true,
})

To Reproduce

You can reproduce based on the above information

Codesandbox URL

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Reproducible Steps/Repo

Steps to reproduce the behavior: This is included in the description.

Expected behavior

We expect after flatten, the messages should still work with hash placeholder with multi plural rules

Screenshots

I have attached screenshots above as it is easier to follow the sequence there

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context

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