Self cancelling indicator issue

Hi,

We bought a new Fabia petrol 1.2 in January this year. All is well except:

When recovering from a shallow right turn to straight ahead the traffic indicator self cancels. Turning through the same angle and recovering to straight ahead from a left turn needs a manual switch off.

Turning through a right angle in either direction the auto cancel works on returning to straight ahead.

Taking the same corners in my older Mk1 always automatically cancels the indicator.

We have taken the car back to the dealer/garage who declares there is no fault found.

Anyone else had this happen – or better, a fix for this?

Thanks