In my case, the egg boiler only boils the water at the back. This is also visible in the boiled water spots on the heating plate, which are only on the rear edge. The eggs are only cooked to very different degrees. Is this normal?

does it have swiss or european plug?

We recently got this Severin egg cooker, but the eggs come out completely hard even on the lowest setting: both egg white and yolk are hard. Does anyone else have this problem? Is it perhaps just our appliance that has a fault?