I am closing this report because 1) it appears to be a result of a typo; 2) os.stat works fine for me (also on Windows); and 3) I am 99.99% sure that IDLE does not delete user code object attributes.

If a system has two files with the same name in two different directories and one manages to run python twice with the different directories as current directory, so that the same name referred to the two different files, then os.stat might return different values for particular attributes.

But IDLE is not Python.  It is run by some python.exe and it sends user code to the same python.exe for execution (with exec()).  So running code with IDLE cannot delete the attributes of objects created by user code.

(musiquegrame), you can still post the result of checking.