Dongle used on Raspberry Pi as many. I first noticed unexplained cuts my Internet access, and I thought my guilty WiFi router. But no: the dongle was hot (impossible to leave my finger on it). I then thought to a problem of RPi (powered by a 1.5A adapter) but the problem is repeated on a USB HUB powered separately.
The problems are repeated to the point of systematic today (they appear in minutes).
All joking apart, I wonder how such heating does not represent a fire hazard.