Thanks We have had several conversation about this and he hasn't come up with a solution. I pointed out multiple photo of very similar stairs on his website none with this odd bump. I think he needs to take down and completely redo

Pull up this website and go over it with your contractor: http://www.ljsmith.net/. This company makes a huge percentage of all the stairway parts used in the US by contractors. Show him that none of the stairways use that. It sounds certain that he pieced two sections of bannister rather than using a single piece, causing the bump. Email a photo of the offending bump to the email address for the website and ask them to diagnose it. If they won't help, I'll ask my contractor to look at it for you. - Susan

susan.mcmonagle@gmail.com

Thank you this is super helpful!