Upon entering I've been getting message that area is unnatural. Bonuses classes like ranger / druid should get do not apply.
I am not certain about quest areas there, but main on certainly is not natural.
Can it be fixed?
Grand Garden Seam.
Seam is key here.
That means you are in another plane outside of the natural world which in turn makes the area unnatural even if it is a "Garden".
No shit? Then why moldmire seam and grand fissure are natural places?