Great minds, Jason.
I did the same thing. 
So I got a reply from the Dracula seller. He wrote:
"Hi Jeff.
Thanks so much for your patience!
After looking very closely at the fold line on the front, I would say that it has been touched up. By shining very bright light onto it, you see a difference in the reflections, with the touched up line being a little dull- but a pretty subtle difference under normal light! I would thereof speculate that this must have been done years ago, with the paper developing some patina over it?! Color used seems to have spread out a bit on the front- probably a soluble colorant-, but absolutely no bleeding through in the lower left quadrant of the folded out poster to be found verso.
But still, a very unusual piece of Dracula movie memorabilia with the geometric alien-like green Dracula on the inside, really reminding me more of Nosferatu, than the Dracula "without teeth" in this movie...
Let me know, if I can be of any additional help!"
So it sounds like it had some kind of touch up, maybe number of years, ago. And if water soluble, like the seller speculates, then not a totally bad thing, as any restorer might also have touched up that fold line, had there been ink breaks or small holes or tears. The good thing too, no bleed thru to the verso, so that's good. That re-touching might also be able to be removed, if desired, too.
And that -- is the rest of the story.
