I'm thinking maybe you have them adjusted too tight, the parking brake is hung up or quite possibly the backing plates have deep grooves worn in them where the shoes slide while moving during braking.
I also lube up the star wheel adjuster threads with anti seize and put white lithium grease on the contact slider pads where the shoes slide on the backing plate.
Pull the parking brake with drums on then release it to see if it is hanging up then step on the brake pedal then release to see if that is causing problems.
You can also get a helper to lightly step on the brake pedal while you watch with the drum off and see if it all snaps back in place like it should. .