I'm having trouble opening your file so I'm not positive - but how long has it being doing this? Meaning was it working correctly before and now it's doing something strange?
In summer mode the wipers do a strange manuever related to "parking" at the lower position on the cowling when you turn them off. Of course when in winter mode they don't park lower so there is no need for it. I'm suspecting what you are seeing is normal although I can't explain the binding noise you mentioned.
It would be easy to see if I could just open that file
OK...got it to open....I'm not seeing anything wrong there....