Like any oven, I expected some odor/fume to come out on the first few runs. But this oven is no ordinary oven in that respect.
Upon its first run, it produced something that I have never smelled before. It was so toxic, that it gave me a bad headache. And the smell did not go away even after a few runs.
So I decided to open it up and see what's causing the odor.
Opening the hood was quite simple, just pull the drawer out, and remove a few screws. Then the top is open.
Then there was the source of the problem - masking tape! Masking tape is used to prevent electrical shorts between the aluminum foil used to cover the insulation material and the controller PCBs. Even though there's heat insulation material beneath it, the tape gets hot enough to produce that nasty odor. So I removed all of the masking tape, and replaced it with Kapton tape, which is heat resistant.
(Sorry I forgot to take the picture of the masking tape before removal. You can see some pics here
This mod took care of the odor completely.