Drawings glitch and flicker after creating them

I just got Storyboard pro, and absolutely love it except for one major issue. After I draw a line, for example, if I try to draw another line, the first one starts malfunctioning. It starts to flicker and pixelly bits of it disappear. The line I am currently drawing can start to get messed up too. It can also start to flicker and as I move my brush, the outline of the brush can leave a trail. From what I’ve seen, If I leave the line alone for a little it will warp a bit from smoothing and then will be fine. But it takes about a second for that to happen and slows me down while drawing a lot. I looked online and couldn’t find this problem anywhere. I really hope it’s fixable. Thanks.

You can try going into the software preferences and setting the “Delay
before drawing vectorized stokes” lower (Advanced tab).

It may help to update the graphic card. If you have two active
monitors, see if it responds the same when you boot the computer
with only one of them active.