Wear A Fucking Mask!
I never charge mine directly, I always use an external charger. I believe that to be safer for the battery and the device. That being said I thought I would give it a try and see if the same thing was happening with my device. I first plugged the USB cable (they do send a nice one) into my computer and the TM didn't even get warm, but would probably take forever to charge with this method. Then I plugged it into a fast phone charger and it did get quite warm but not too hot to hold/touch. But this would only happen when it was charging, not when using it, and I don't think you can use it while it is charging anyway, so I am not clear why this is a problem. During normal use that plate never gets unusually hot tho the body gets quite warm and I usually let it cool down a bit between loads or after doing two loads in a row.