I didn't have to lever the drum off. I could pull it off, after releasing the automatic adjustment. No force needed.
The brake felt a little warm, certainly not hot.
I expect all the steel for brake shoes is soft metal. None would use quality, hard steel.
That leaves only the Gremlin theory. Hope I can scare it with brake cleaner.
And I'll rewrite the brake part in the factory manual. After working on the brakes a short drive with hard braking, to settle the brakes. Then release the adjusters and a second drive to set up the brakes again.