To all that have issues regarding their dash melting. I work for a dealership, Toyota Australia are aware of this dash melting concern other than Aurions. (Prado 120 series, ZRE152 Corolla) The reason they excrete sap/wax substance is from high humidity or high temperatures.
If your vehicle meets age requirements (vehicle is 10 years or younger since first production date) and have clear visual melting of your dash. Toyota should replace your dash pad under a customer satisfaction exercise free of charge. I know this fix wont be available forever so if you do have this concern, take it to your local dealership now. Hope this sheds some relief for all you follow members. :)