Pnp are bad players. Have you checked to see how much current there sourcing. I still stay there not t turning on like they should
What I see happening is your not pulling the PNP low enough. If your feeding 12 volts the base is only pulling down to 2.5 volts it needs to be below 2 volts if your using pwm. take some readings at the base to see if it's going low enough.