|Grizzly the Archer|
I can see why you think that.
It's either: terrain bond allows the surrounding terrain to act as your terrain (making the mountains turn into your +6 forest), or having your terrain bonus transfer to the terrain (now you have +6 mountains since your in mountain).
If its the first way, then your correct, it wouldn't change the terrain and thus terrain dominance doesn't work for that new terrain for your benefit.
However, if it is the later, than terrain dominance does work with that new terrain, md you get the benefit of terrain dominance.
It's strictly based ff the wording off terrain bond which states:
"You call upon the spirits of nature to help you adapt to your environment. You treat the terrain you are in as your most favored terrain until this spell ends.
If you do not have the favored terrain class feature, you gain no benefit from this spell."
The issue here is, TREAT. Which way? The former or the later of which I wrote above?
Needs an FAQ.