[Python] mypy exclude option is not working - bug?

MRE:

• Make a folder (let's call it MyProjectFolder).
• Make a helloroot.py empty file.
• Make a subfolder named FolderNotIgnored.
• Make a hello.py in that subfolder.
• Make a mypy.ini file containing:

[mypy]
exclude=FolderNotIgnored/


The tree will look like this:

│ helloroot.py
│ mypy.ini
└───FolderNotIgnored
hello.py


Open the terminal. Run pytest --mypy.

We expect mypy to ignore FolderNotIgnored\hello.py.

However, I get this:

================================================================= test session starts ==================================================================
platform win32 -- Python 3.12.5, pytest-8.3.4, pluggy-1.5.0
rootdir: C:\Users\CENSORED\Documents\Challenges\MyProjectFolder
plugins: anyio-4.8.0, hydra-core-1.3.2, mypy-0.10.3
collected 3 items

FolderNotIgnored\hello.py .. [ 66%]
helloroot.py . [100%]
========================================================================= mypy =========================================================================

Success: no issues found in 2 source files
================================================================== 3 passed in 0.10s ===================================================================

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