Expected styles from a private modules are missing in the production client bundle

[navanjr]

Description

We have private modules using @nuxt/ui.
Their module setup uses nuxt.hook to add files to tailwindcss.config.
with...

// nuxt.config.ts
tailwindcss: {
    exposeConfig: true,
}

We can see at runtime our private modules were included in the tailwind content.
This is also confirmed with logs during the build and nuxt.hook

Everything works as expected when building locally...

npm run dev

or

nuxt build

However when building for production the resulting client bundle is missing any style used in a module.
in other words, anything from tailwindcss.content with node_modules in the path was skipped.

My modules tailwind styles don't work in production.

How can I debug this?