Electrical – Is an oven heating element polarized

It sounds like the problem might be with the fan. You may need to access the fan from the back (outside) of the oven; or maybe to access the fan you would unscrew the screws circled in red.

Edit- If the fan is not the problem (and the warranty is expired) then I would order a couple more of those retaining clips. If the clips don't come with screws, then you could probably use high temperature screws (like for stoves).

Edit2- Manuvering the element while is it hot and pliable would be the best way to avoid cracking it. Generally speaking, this is kinda dangerous; if you do this you should be prepared. Have a friend ready to call for an ambulence. Of course you should wear gloves. And if you don't get hurt, you might still need to order a new element.

But (that being said) you could try heating it up and manipulating it with a couple pairs of pliers or channel locks. After repositioning the element and allowing it to cool off, you would then intall the extra clips.

Edit 3 if the price for the element is cheap, then I would get another element rather than try to fix the old one... or if you tell them it warped after a couple weeks, they might give you a new one or some kind of discount.

Probably because it's a 240V oven, and the oven thermostatic switch only switches one side of the 240V.

American power is 240V, but wired with a center-tap on the transformer, with neutral attached at the center-tap and ground bonded there. This gives 120V from either "hot" wire to the neutral, which is how most of your receptacles are wired. Your oven uses both "hot" legs, with 240V between them. It is also grounded to the center. If the thermostat switch only switches one leg, that is adequate for controlling the oven, but it means the other leg is always connected to the heating element, so it is 120V above the grounded oven chassis.