Brush strokes shifting when drawn + disappearing

Whenever I draw lines, the strokes shift to the left a little and vanish in some cases. I had to redraw part of the 'H' in the above gif as an example. Does anyone know how to fix this?

I use a Mac OS X and a Watcom Cintiq 16. This problem does not show up in any other program (photoshop, illustrator...) aside from animate. I'm using the latest version 21.0.4. I also recently uninstalled and redownloaded the Watcom driver, but the problem persists.