PS 2025 Color Dynamics not doing what it's suppose to

[adamt18510785]

The foreground background color dynamics to paint from one to another with pressure only seems to be working only half the time or not at all with the bg color only working on pen liftoff. 

I either get just the foreground or just the background on the initial stroke, I've played with all the settings it's not me. 

On both machines and with huion and wacom tested

M1max or Ryzen 9950x