Thought I would show this, looking for thoughts on this cover. First glance, I thought no big deal, until I noticed no printing of the image across the perfs. Then I got to looking closer, and you can see a ridge where the perfs are against the stamp. I look closer and you can see little touches of glue. I wonder, why someone would glue perfs, maybe this was a imperf stamp and they were afraid the post office would think it was a forgery? Or maybe sales were slow that day, and the sender had nothing better to do. What do you think?
So back to the reason there is no cancel ink near the paste-up. The paper on the top part of the paste-up is not level with the lower portion thus forming a small "step". The cancelling device was unable to strike that section. A paste-up on cover is a nice find.