This information is very helpful. Have you tried to google for possible solutions?
For example, this one is interesting:
The problem is that user site packages are attempted to loaded (...user_site = getusersitepackages()...
). They shouldn’t be loaded (see here).
Does any of the followings work?
./PythonSlicer
./PythonSlicer -s
./PythonSlicer -S
Does settings PYTHONNOUSERSITE=1
environment variable make any difference?
Can you investigate why user site packages loading is not prevented (by reviewing content and adding print statements to the .py files listed in the call stack)?