I have tried multiple times to see if this was an issue with my supervised classification, but I don't think it is. I created my training samples and created a signature file. Per my course, I need to run Maximum Likelihood. However, every time I do, my first class fills in extra border(s) around my results.
I am running ArcMap 10.3. I have attached an image of my Landsat5 imagery before I ran the Maximum Likelihood classification, as well as after (which is the issue I am having). If I had to guess, this is something very simple I missed.