I can make the sketch register as being a closed contour only if I explode the blocks that make up part of the edge. I have found this to be a know problem based on a Reddit posting however I haven't found any mention of it on this site. I know that I can also, if I want to keep the blocks un-exploded, use the original sketch with the blocks as a reference sketch and then convert entities on a secondary sketch. I'm just looking for a cleaner simpler option as I can see this being a regular occurrence.
Thanks for any help.