I haven't started having this problem until i started using Krita 4.4.8, if i were to choose a dark color (usually a shade of blue), and chose a color a bit lighter than that color, I wouldn't be able to use the blending tool to make a smooth gradient between those colors. the colors would only move around without mixing

here is the drawing that i'm currently experiencing this on, the character is wearing pants and on the left side of their pants where it's a darker color i can't use the blur tool, or any brush that blends to make a smooth gradient between the dark side of the character's leg and the light side



Here I tried to replicate this issue on a new canvas with two colors that do the same things that I just descibed



I also tested this on Krita 5.0.0 and i had the same problem there with this drawing, and i'm also currently using krita 4.1.8 because I've also started having this problem no that version also