My sp01 is consistently having way more unburnt gunpowder residue from s&B 115 rounds than my glock. What could be causing it?

I have the cajun sao kit installed with a 12lb spring.

Is my spring too weak. Should I pun it a stronger one so that it doesn't cycle back as fast.

I thought the reaction that happens when a bullet is fired happens so fast that the round and the gasses exit the gun before the slide even goes back but I'm finding this unburnt powder all over my frame. There was even some on the sear cage. It added a lot of grit to me trigger because it was all over the trigger bar