Including package data: Error when using --no-build-isolation

[VeckoTheGecko]

I’m looking to include some text files in my Python package, and found this article on the SetupTools guide. It suggests as an option

[tool.setuptools.packages.find]
where = ["src"]

[tool.setuptools.package-data]
mypkg = ["*.txt", "*.rst"]

It works well locally however for some reason is failing in CI with conda (micromamba and miniconda). I have created a minimal reproducible example project (https://github.com/VeckoTheGecko/micromamba-testing/). Either removing the —no-build-isolation flag, or changing the following line fixes it.

 [tool.setuptools.package-data]
-my_package = ["*.txt"]
+"*" = ["*.txt"]

See the main and failing branches of the example repo for CI output.

Tried unsuccessfully to reproduce in the micromamba docker container, so perhaps this is only with the ``setup-miniconda/micromamba` actions?

Does anyone have an explanation for this? Maybe this is worth clarifying in the docs?

(PS, I realise that the [tool.setuptools.package-data] block isn't necessary when using setuptools-scm in that example project, question still stands about build isolation)