Please send us a video of this occurring to support[at]astro-hq.com.
What is the year of your Macbook Pro?
Try turning off Use ColorSync in-app, and see if this makes a difference
1. Quit the iPad app, by pressing the home button and swiping up on Astropad
2. Launch the Astropad Mac app
3. Go to Astropad's top menu bar, hold down the option/alt key and at the same time click "Preference"
4. This will enable the Debug tab, click it.
5. Then turn off "Use ColorSync".
Relaunch Astropad on your iPad.