Hello, my tablet pen is stuck on the eraser brush. I just had this same issue a couple hours ago and resolved it by pressing ctrl, but it's not working now.
To elaborate, I have the actual "paint" brush selected, but when I make a stroke with my pen, it records an "eraser" stroke in the history, no matter what I do. But everything works just fine with my actual mouse.
I have tried pressing the capslock, ctrl, and restarting the program, and nothing is working.