You don't mention which Gaggenau steam oven you have. There are 2 different models. One is a plumbed version and the other is a water tank version.
They are very different in their build and where the heaters are located.

Hi Jakvis, my oven is the plumbed version. it is the discontinued model ed220 27" aluminum.
thank you!

We have the discontinued 24" version. We haven't used
it very much yet (just moved back in Thanksgiving), but
we noticed when roasting veggies that the front right corner
get a bit overdone. Sorta unexpected, since the heat
comes from the left. I'm wondering whether it is the
heat from the halogen oven light.

attofarad, i think you might be right. mine also heats things faster on the right side, maybe more towards the right front.
i read the manual and it did mention that the light is turned off at lower temps, but on higher temps, the light also contributes to the cooking. this seems like a design flaw since the light is not centrally located..? i wonder if there is a way to even out the temps on both sides, like putting a mirror in there or something?

On the plumbed version the heater is on the left behind the cover and the heat blows out the back and I think bottom of the cover and circulates back to the middle of the cover. You also need to make sure the grease filter is clean to ensure non-restictive airflow.

Hi Jakvis, thanks so much for the info! I will check the grease filter. I never cleaned it since install. though i haven't used the oven all that much to accumulate a lot of grease, but it doesn't hurt to clean it. thank you!