During the painting process with wacom/Veikk tablets i had the annoing issue where after you painting something on point A and going to point B the application decides to paint a straight line, i was have this issue in 4.9 as well and i think even earlier, i just don't use tablet in 3d coat before, so i use ctrl+Z every 20 seconds when painting. I was check on Wacom and Chinese tablets, they both almost new and work fine in other apps, but not in 3d coat, Mode in settings TabletPC
2021-04-10_15-15-52.mp4