It appears there's an incompatibility with pycodestyle and python 3.12.0b1 (latest beta version).

You can check by running this in a docker container, this creates a minimal example showing this warning:

docker run --rm -ti python:3.12-rc /bin/bash echo -en "import sys\n\nif 1:\n pass\n" > test.py pycodestyle test.py 

Output is:

test.py:4:1: W391 blank line at end of file 

Same with the git version of pycodestyle. This does not happen with python 3.11.