I reported this to both AstroPad and Smith Micro (the Clip Studio folks) back in May of last year. I’m not doing any artistic drawing, I’m using Astropad and whatever drawing program on the Mac to capture fast handwriting. The impact of this bug is to make your handwriting look a lot messier than when you’re using pen on paper. It’s a problem with Clip Studio Paint not giving having a fast enough sample rate for their input devices. As I recall, the issue was more pronounced when you first started a fast stroke - once it realized you’d actually started drawing it began paying a little more attention (although still not enough compared to other programs e.g. SketchBook Pro).
This was the last I heard from Smith Micro about it (although the sense I got was that I was the only one who had complained about it and it likely wasn’t going to get much attention):
JUN 10, 2016 | 11:45AM PDT
As stated previously, I have filed a report about your specific issue.
To clarify… when I contacted Autodesk, they indicated Sketchbook has support to work with AstroPad on Mac Systems.
Clip Studio Paint does not indicate support for input devices other than Wacom Tablets.
We have several users that state the software works with AstoPad on their Mac systems.
John Csaky | Customer/Tech Support
Smith Micro Software, Inc. | http://www.smithmicro.com