Looks like this issue will pop up again if one use a remote environment in PyCharm, because PyCharm somehow forget to sync these *.pyi files to the local remote storage.
Solution: Manually mapping the local remote storage to the remote path, then sync *.pyifiles to local would solve these problem.
Plz spread this tip so nobody suffer from these annoying falsify inspection warning again
PyCharm has its share of small bugs like this, but in my opinion its benefits far outweigh its drawbacks. If you'd like to try another good IDE, there's also Spyder/Spyderlib.
You can locate the path to local storage at the Project View -> External Libraries -> Your Environment -> Remote Libraries, then right click and choose "Copy Path"
Please look out if there is any update in you IDE.
If this helps you let me know.