Hello @bentraje,
Thank you for reaching out to us. The reason for this behavior is that you are here using a Python interpreter in a shared environment. When you launch a Python script with a standalone Python interpreter, e.g., CPython 3.11, the working directory of the interpreter is set to be the directory of the interpreted py
file. This is then expressed by os.getcwd
which returns that working directory:

Python then makes all its magic relative path thing happen with this path; all relative paths are relative to it. But for a Cinema 4D plugin, the working directory is the application directory and not the plugin directory because here a shared interpreter is running.
import os
print(f"{os.getcwd() = }")

One must construct local paths manually in this case. The common way to do this is the __file__
attribute of a module, it will always contain the location of the module file, no matter where it is on a machine.
import os
ROOT_PATH: str = os.path.dirname(__file__)
CONFIG_FILE_PATH: str = os.path.join(ROOT_PATH, "config.json")
print (f"{__file__ = }")
print(f"{ROOT_PATH = }")
print(f"{CONFIG_FILE_PATH = }")
__file__ = 'C:\\Users\\f_hoppe\\OneDrive - MAXON Computer GmbH\\support\\pc14379\\pc14379.pyp'
ROOT_PATH = 'C:\\Users\\f_hoppe\\OneDrive - MAXON Computer GmbH\\support\\pc14379'
CONFIG_FILE_PATH = 'C:\\Users\\f_hoppe\\OneDrive - MAXON Computer GmbH\\support\\pc14379\\config.json'
Cheers,
Ferdinand