msvcrt.getch prints twice inside loop

[ReallyBigTeeth]

I just realised I have one Windows 10 computer not updated to 1803 yet, and sure enough, msvcrt.getch() does not return the scan code. Only one call to msvcrt.getch() is made when in a loop:

The same script as before only returns the key pressed:

Output:
loop 1
b'e'

What changed with Windows feature update 1803?