Can you post the model number please.
Also im taking it we are talking about 2 different appliances here.
Ok I know which one you have.
Now its going to be a fault on the timer clocks. Ive replaced quite a few of these in the past for this fault going off.
The new timer has been modified from what ive heard to stop this from happening.
So the timer clock will need to be replaced to cure this.
How old is the oven? As these do have a 2 year warrenty but if its just over then still give them a bell. As Fisher + Paykel are usually very good on after care service. Just give them a bell and tell the fault you have and hopefully they may do it free for you as it has been a common fault ive seen on these range cookers.
If you need anymore info just get back to me.