App crashes when I select Watercolour Live Brush

Hi all, hope someone can help. I use Fresco on Surface Pro 8 and it was working fine. But now it crashes whenever I try to use a watercolour live brush. Another odd occurence is when painting with a live oil brush, a fine grid of lines appears on the canvas meaning I can't use those brushes either. Fresco was working flawlessly...whats happened?!