Using wax paper instead of parchment paper for baking can lead to problems, as wax paper is not designed to withstand high temperatures like parchment paper. The main concern is that the wax coating on the paper can melt or even catch fire in the oven, potentially ruining your granola and creating a fire hazard.
It is not advisable to eat the granola that was baked with wax paper. If the wax paper has melted or charred, it can release harmful substances and affect the taste of your granola.
To be safe, it's best to discard the granola and start again using the correct parchment paper. Always double-check the materials you use for baking to avoid any potential health hazards or unwanted outcomes.