Why doesn't hatch find an installed python interpreter to be used in a test environment ?

[manuel-koch]

I have a python project inside a sub-directory of my git-repo.
The pyproject.toml contains this snippet to configure python interpreter for the test environment(s):

[[tool.hatch.envs.test.matrix]]
python = [
  "310"
]

This python version seems to be installed:

$ hatch --version
Hatch, version 1.14.0

$ hatch python show
    Installed     
┏━━━━━━┳━━━━━━━━━┓
┃ Name ┃ Version ┃
┡━━━━━━╇━━━━━━━━━┩
│ 3.10 │ 3.10.16 │
├──────┼─────────┤
│ 3.12 │ 3.12.8  │
└──────┴─────────┘

But when I try to run tests, hatch can't setup that env !?

$ make test
cd src \
        && hatch run test:cov
Skipped 1 incompatible environment:
test.py310 -> cannot locate Python: 310

I have tried using 3.10 as the version string too, but that isn't found either.
It works though when using 312 as the version string.