Consider the following file repro.py:

from datetime import date, time  # noqa: F401

And let's say my ruff config has isort lints, with force-single-line option:

[tool.ruff]
fix = true
select = ["F", "I"]

[tool.ruff.isort]
force-single-line = true

Running ruff repro.py results in the time import being deleted:

from datetime import date  # noqa: F401

Running ruff repro.py --unfixable=F401 results in:

from datetime import date  # noqa: F401
from datetime import time

So the problem here is that the # noqa comment is not reproduced on the extra lines. Desired outcome would be:

from datetime import date  # noqa: F401
from datetime import time  # noqa: F401

This is on the latest version of ruff (0.0.254).