Wiper goes nuts!

[Olazz]

Looks suspiciously like the tape is missing. It's a slightly opaque gel-like pad.. You'd know if it was stuck to the sensor.

 

[CANEX]

That's what I was thinking.
I think I'll get a new one - although I have just got a stone chip right in the middle of my field of view - so I might need a new screen anyway.
Do the other settings apart from the 'A' have any effect on your intermittent settings? Mine just go haywire whatever int. setting they are on.