My octavia has got an adolescent rear wiper. Basically it does what it wants. I can push the stalk forward to go onto intermittent and it sometimes doesent work or i will wip the screen about an inch at a time or just flick it on and off and it will go and go and go the most i have counted is 13 times. It is really annoying 

Probably needs a new wiper motor.

 

You might be able to remove it and fix it by re-greasing the internals although it may not last long.

Same happening to mine. Doing my nut in 

Water in the motor. Best way to fix for good, whip motor off, open up, clean regrease mechanisms, take wash pipe off and plug with bolt.

No more future problems, full working wiper never have to worry about water in the motor or even the boot again.

Downside - no rear wash. 

Rains enough in this country anyway, who needs it.