The years old bug continues, using huion kamvas pro 13 corel painter 2020 still changes brushes randomly. I'll go back to corel 2018 which is pretty bug free with huion products.
Download the drivers from the manufacturer's website http://www.huion.com/download/ "Driver_14.8.90". This version of the driver helped me with my graphics tablet Huion Kamvas Pro 16. I had the same problem before, but I don't have anymore.