Our crossbars are pre-galvanized welded steel tubing so moisture will most certainly induce oxidation. However, it is normal for the inside of the crossbars to show a small amount of rust and there is nothing to worry about structurally because of the thick gage steel wall (.085” thick). Keeping Endcaps on the bars will keep this from becoming a functional problem for years.
If you feel this is a warranty issue please contact us here to begin a warranty claim. Be sure to include photos of the rust these can be attached at the bottom of the ticket.