King Comics never published Flash Gordon 12, because they went out of business. Jones was told by his editor he could still get paid for the story if he turned something in quickly; he didn't care what was on the pages. So Jones rushed it out, not expecting (or wanting) the story to see print. He was a bit shocked, even horrified, when Charlton printed it in their Flash # 13, behind a Pat Boyette cover.
Fascinating....that explains a lot. Still, there's a few parts that are che nice (then suddenly, it goes all squiggly)