We are so sorry for the delayed response to your issue with random dots appearing on your canvas when using the retract function within the range of your Wacom tablet. I hope the issue is resolved with the latest version of Fresco or Wacom drivers.
If not, to better assist you, it would be helpful to know if you are accidentally pressing any keys, such as the Ctrl key or a pen button while using the retract feature. Sometimes, certain key & button combinations can trigger unexpected actions in the software, including drawing random dots on the canvas. If that is not the case, please share a screen recording demonstrating the issue. It would be really helpful for us.
Thank you for your patience and understanding, and we look forward to resolving this issue for you.