[Zubersoft]

This one is going to be difficult for me to investigate. With the S-Pen, if I set the eraser to "Draw Box" and hold the stylus button, it draws a red box and erases what is in that box. I'm not able to reproduce the issue in your video where it just deletes the entire annotation. That almost seems more like it's triggering the undo than using the eraser functionality to be honest. Can you please verify that the stylus button tool is set to "Eraser"? Also, verify that the two finger tap either isn't set to "Undo" or temporarily set it to something else to verify that isn't involved. You clearly aren't touching the screen with your fingers in the video though, so I doubt that is the issue. There must be some fundamental different between our two tests. I will keep experimenting.

As far as your 3rd party pen, I'm going to send you a link to a build to test. It should hopefully fix the issue with the eraser on your stylus not working. 

Mike