What kind of keyboard or tablet are you using? Are you running any side-car or companion apps that do screen captures or help with DJing? It sounds like your shortcuts are getting hijacked. You can change the shortcut for the Eraser tool via Edit > Keyboard Shortcuts choose Tools and remove E from the shortcut for Eraser. I've a feeling that will cure some of this, but I think the root cause is that the app is receiving incorrect or anomalous input from hardware or (rogue) software.
