We experienced the same exact problem on our 2015 Axis 24.1.
Defrosters on full, and A/C running did not prevent the side windows from fogging up.
In the end I found that poor workmanship in the engine compartment was the cause.
Check the screws and brackets on both drivers side and passenger side in the engine compartment. A couple of the brackets were loose, and the foam seal broken.
Mounted and sealed the entire support inside the engine bay, and the problem went away. I used a combination of pressurized RTV, and foam sealant to get up there with one arm.