My SSL 2 interface only pans left in stereo

My SSL 2 interface will only pan left when the input is set to stereo. At first I thought the problem was in my fortin nameless suite guitar plugin but I discovered that the input only panned left when I wasn't even using the plugin and the stereo button the interface was engaged.

Picture of the interface with stereo button engaged

When all the inputs are set to stereo in reaper and in the plugin, it does not pan right. If I set the input to mono in reaper, it pans right fine. If I set the input to mono in the plugin, it pans right fine. The problem is when all are set to stereo. I've had this problem on and off and I cannot figure it out. Can anyone help me out? Thanks.