This might be the result of
This might be the result of a seal issue around the doors or the glass. The manual states specific remedies through using the Air Conditioner for interior fog/humidity build-up and exterior icing.
Always remember, A/C turned on will De-Humidify the interior air and dry it out, You should use A/C turned on with Heat if you want to avoid interior humidity build-up and fogging.
If you still get fogging in the interior despite using A/C turned on all the time, perhaps there is an issue in the A/C system with the evaporator, or the condensation in the A/C is not being dried up properly. It could be that the hose that allows water/condensation build-up in the A/C system to drain is clogged up and so more condensation is still coming through the A/C system than should be.