Fake-Out Harmony 10.3 Prob

Heya,
I’ve been having an issue with Stage(Harmony 10.3/ OSX 10.9.5/ Cintiq 21UX) Where it will, for example, show line A having being drawn with the line tool, but then you go to draw line B and line A vanishes as if it weren’t actually placed yet.
With ‘show contour’ on I can see this is actually the case with offending lines not showing they contour after being placed. It happens sporadically(sometimes many times in a row, sometimes I can almost forget about it).
This happens with many other things such as; selection, stage rotation, pen, brush, etc.
It’s like on pen release the command isn’t taking place, but it’s definitely not just the pen being funky as it will let me go to do the click B and not ‘undo’ click A until click B has happened.

Guess this shoulda been posted in help/troubleshooting…Can a friendly or grumpy moderator move this topic over there-ways?