Hi Sean, so your little dot is not a totally extra thing hanging out there, it's this edge from the top face:


If you zoom in to the top there you can see that edge is some slight distance to the right of the other ends:


However, again this distance is just 0.0000168 units, so it's like some fraction of a flea's eyebrow hair off, and well within tolerance, so it's totally fine.

If I was able to see exactly how you built that area I might be able to suggest some other way of doing it that would make the accuracy even tighter but the current deviation is so small I'd recommend just not worrying about it. It's normal with any kind of CAD model for edges to be off by orders of magnitude more than that, although often times with planar geometry it can be all exactly aligned like you were looking for. It depends on the particular things you're doing though, and it would probably help if your model was a bit bigger, like probably if your model was 10 times larger in size that particular calculation would have still gotten down to 0.0000168 units but then that's another 10 times tighter.

Hope this helps, as best as I can tell your model is totally fine and should print ok.

- Michael