Author Name not showing correct Author in byline

I installed and set up my site for my client at https://www.polygonpusherinc.com/blog/ ... My client has logged in as himself, created a blog post and on the blog page it shows me as the author. I opened the post and under author his user name "polygonpush3r" is selected. Yet publicly it shows as my username. as far as I can tell it seems to be some kind of glitch in the theme. Please help me figure out how to fix this. thank you!