Hello!
I had this problem at least twice now, and want to report it.
When using the brush repeatedly, while having pen pressure on, affinity designer freezes and crashes,
after a few quick brush strokes.
I tried it without the pen pressure and it works fine without it, i think.
Only setting I have changes i that I disabled Windows Ink inside of Affinity Designer and on my tablet.
I don't have any issues with pen pressure on Affinity Photo,
so I personally think the vector brush tool in Affinity Designer with
pressure sensitivity ON is just bugged.
Hope you can reproduce this problem and fix it.
Thanks for your time and patience!
Extra Specs, just for good measure:
GPU: RX Vega 56
CPU: Ryzen 5 3600 CPU
Graphics Tablet: Huion Inspiroy 950P.
RAM: 16 GB of something.
affinitybrushbug.mp4