When I make a selection in Photoshop and then apply a Bokeh effect, I get ghosting around the edge. All I'm doing is making my selection, cleaning it up with Refine Edge, and then apply a Bokeh effect. What's going on?
The Refine Edge tool is the cause of the problem. Read more about this tool, here. If you do not use this option, it should take care of the problem.
Here is an animated gif that demonstrates this. Notice that when you encroach too far into an area, you see this problem. This is because you are blurring those pixels, causing the ghosting effect. It's more prevalent in lightly colored areas.