I think I have accidentally changed settings on a brush while painting without realising it, but when I go into the brush settings tab I can't see anything unusual. The brush is bristles-3 large smooth. Now when I paint with a light colour it appears on top of everything previously painted without blending and if I use a dark colour it appears below everything without blending. I am painting on the same layer and the layer type is normal. Other brushes are working fine.

I know this is probably a really simply fixed issue but I am far from knowledgable about krita so I could really use some help.

Worked it out I had the pen tool on overlay somehow.