Animate Eraser doesn't always erase

[Moderator merged with original topic.]

Everything seems to work fine. I create some lines and shapes with the brush tool. I made a mistake and try to erase a segment. I push down with my pen on my tablet. The line is erasing. I drag the pen through the line I want to erase. The line keeps erasing. Then I pick up the pen. And poof, the line that was supposed to be erased suddenly reappears like I never touched it.

This seems to happen more when the lines are connected to an overall shape. For example, if I try to erase a part of a finger on a fully drawn hand, it will reappear. If I do quick strokes over and over, I can sometimes get smaller bits to erase. 

This is extremely frustrating as it will on and off work and stop working. I have fully updated my computer and my wacom tablet, but it is not helping. I'm not sure if the problem is the tablet or the app itself. 

Changing the eraser mode and size does not help.

My computer is a surface book 3.

My Wacom Tablet is an intuos pro.

Maybe mess with your surface pro pen settings. Here is a tutorial that might help. https://www.youtube.com/watch?v=4LiVX9jq8_U

that's expected with certain erase modes and erase settings.

ie, to work like you probably expect, select erase mode normal and an eraser size at least as wide as the line.  (and remember, this is a vector drawing interface so you're not going to see pixel perfect anything in animate.)