I had the same issue on one of my dual pane windows last year. I found a company that can fix them. They take the whole window and frame out, reseal the glass panes and replace the window. Was fairly reasonable cost.
You can internet search for ones in you area. When I was looking I found many companies across the US that performed the work.
Scott & Donna
2013 Dodge Ram 3500, dually, Aisin, 4.10
2014 Keystone Fuzion 404 Chrome.