40 is your answer, 40 + 2 is the expected one. Not a kata issue. You're returning inside the loop at its first iteration.

Issue zith this one, in my local IDE it passes the tests, but fails here, because it seems the numbers in the test are rounded down.
Example: expanded_form(42) error: 40 should be equal 40 + 2

Any idea how this can happen?

Yes, that was what I was looking for the whole time!
Thanks a lot, this was of great help :)

Your function currently prints check instead of returning it. In a Codewars kata, you should be returning the result from your function rather than printing it. Make sure to use a return statement to output the result.

This paragraph has some information on your problem, see if it will be helpful for you.

Python: When in vscode, it succesfully detects pangrams and non-pangrams,
but when tested in here, I am stuck on the error that None value should also be True/False.
Can somebody please help?