I was hoping someone would reply with a fix as my Galaxy Active 2 is now doing the same thing. My screen is completely unresponsive even after using the side button to reboot and the screen is jumping from app to app with accompanying voice. Unfortunately it is 13 days beyond the 1-year warranty.
I have the same issue, the touch is not working, or it works by itself, the watch gets hot, and does weird actions by itself. TBH all Samsung products I use, have issues, I bought the best Note, best ear buds and best watch, and all are just *****, the phone wasn't able to make normal phone calls, the earbuds doesn't work properly, having connections issues, and now the watch.. I'm thinking to move to Apple, I would lose all the money I invested in Samsung, but to those who think about buying Samsung products, I strongly advising you to look for a different company.
My Galaxy is acting in the same manner. Three days ago it registered my resting heart rate at 180 bpm and then began talking constantly about the weather, the # of steps I have taken, etc. I cannot get to settings and have pretty much given up on it.