Brake Pulsing - Finding the error in my ways

I’ve had the rotors and pads replaced 2x in my ‘16 with 72k on the odometer. First time under warranty, second time self install Powerstop kit. Both instances a brake pulsing (when braking) were the complaints. No significant wear and plenty of pad was left. The service department when the first complaint was made, noted that the rear pads and drums were rather dirty and stated that the rear could possibly be causing the pulsing sensation.

Fast forward to recently, the sensation has returned, but now I have another theory as to why it may consistently happen; I use my e-brake always (out of habit, maybe). My thoughts are, brakes get hot, I reach my destination, park and apply ebrake. Now that ebrake is depositing material in one location while the drum is cooling.

Thoughts? My thinking is in regards to typical brake pulsing is caused by a buildup of pad material in one location and not in fact a ‘warped’ rotor.... I’ll break off the drums and clean up the surface and avoid using my ebrake to see if it remedies the issue.