DIAGNOSIS Yeah, this one's common. It's normal for the metal barrel near the cuff (where it attaches) to get quite warm during use—that's where the heater is. But it shouldn't be scalding hot or smell like burning.
FIX First, make sure you're using the correct heat setting for your hair type. Higher settings generate more heat. Try using the medium heat setting and see if it's more manageable. Also, ensure you're using the machine's airflow to coil the hair, not manually wrapping it tightly against the hot barrel, which transfers more heat.
IF THAT DIDN'T WORK If it's getting *excessively* hot on a low setting, or if you see discoloration on the barrel, there could be a fault with the temperature sensor. Stop using it and contact Dyson, as this could be a safety issue.
HEADS UP Always use the provided heat-resistant pouch to store the attachment immediately after use. That metal stays hot for several minutes, and tossing it on a counter or in a drawer is a burn risk.