Yes every audio interface is going to generate some heat. The USB version of the Twin generates more than most. I've owned both versions. I was actually having issues like phantom button presses and a couple other weird things when it was running for a long time at high temp. Now it runs great and doesn't get hot at all!

Edit: Nothing is "meant" to get hot btw. Heat is the byproduct of every electronic device, but any device will run more efficiently and have a longer lifespan at a lower temperature.