Cursor goes crazy, opening apps, closing apps - I have no control.
I got this new iMac in Dec 2019, and started using it in Jan 2020. Since then, periodically I lose complete control of the cursor. I can sometimes notice when it's starting to happen: if I'm keying text in a text box, the letters will start to overwrite themselves. Then menus will start to flicker. I sometimes have to use the button at the back to shut the computer down because I can't get control of the cursor. I then also reboot and I'm fine for a while, and then it happens again. It seems to be getting "worse" (more frequent, more apps opening etc.) as time goes on. The last time it happened, I wasn't even using my computer ... it was woken up by my Apple Watch and then just started going crazy all on it's own.
I use the Apple bluetooth magic keyboard, the Apple bluetooth magic trackpad, and I have an Wacom Intuos PT S which is hooked up directly which has it's own trackpad and pen. I'm using these three objects back and forth and have been unable to tell if one of these is a trigger or not. I have just now noticed that I also had my old keyboard, mouse, and trackpad in the bluetooth list, which I have now removed. Could this be causing the issue? And if not, what?
Here are two links to videos I have taken of the last 2 episodes, both last week. One I managed to start with Screenshot, and I used my iPhone for the other. The sound is irrelevant.
https://www.dropbox.com/s/b5pv2jddk0d5glf/zoom_0.mp4?dl=0
https://www.dropbox.com/s/dg34jiizfh5d1w0/iMac%20Problems.mov?dl=0
The second video is about 4 minutes long and it was the craziest it's ever been. I was not even using the computer that day.
Thank you.
Sarah
iMac 21.5″, macOS 10.13