hashlib.sha256 returns different results on Linux

Question

I am hashing a file including its name from the path component with the code shown below¹. I am getting these strange results (hash value simplified for readability):

Machine	Hash
Windows 10 - local 1	abc
Windows 10 - local 2	abc
Windows 10 - CI - Machine 1	abc
Windows 10 - CI - Machine 2	abc
Linux RHEL 7 - local	abc
Linux RHEL 7 - CI	abc
Linux CentOS 7.9 - local	abc
Linux CentOS 7.9 - CI	abc_linux_other

The interesting thing is

• it always works on Windows, doesn't matter the machine, the user, the patch level of windows etc.
• on RHEL 7 it works, on my local machine, on the CI machine, and if I ssh in the CI machine and run it locally (as different user), it always works.
• and then there is CentOS, where in CI, I get these strange results.

On all machines, the same Python version, even the same Python installation is used!

I have absolutly no clue, where this behavior comes from and where I to look?

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¹ Code

import hashlib
from pathlib import Path

MAX_READ = 4096
some_file = Path("abc/abc.txt")

cs = hashlib.sha256()
buffer = some_file.name.encode("utf-8")
cs.update(buffer)
with open(some_file, "rb") as f:
    while buffer:
        buffer = f.read(MAX_READ)
        cs.update(buffer)