PM NG v18.104.22.168.
I’m not sure whether this is the intended behavior or not, but if I rotate a brush it will change its color to the primary selected color.
E.g. I’ve created a red brush in one layer (global palettes are OFF), and then pasted it in another layer (which happens to have the same palette, although it’s independent from the previous layer). When I paste the brush, it preserves the original color, but when I rotate it changes color to the currently selected FG color. So this only affects rotate operations on brushes apparently.