I think my oven may have been overheating?

[newts]

I think you were very unlucky with your original oven, by design the oven casing shouldn't be getting anywhere near hot enough to burn the carcase.

 

[CXRAndy]

Slightly increase space around oven, improve ventilation, and use isolator plate to separate carcass away from hot spots

 

[tyred]

I had misread this as oven overeating!