Some spots can be inside unusual places, yes.
Like, for an example, in Zzaion a spot appeared to me in a unreachable roof, so it was impossible to finish. Spots like these needs to be reported, so they fix it.
About quests, yes, spots can be inside questing places or places only accessible after quests, like for an example:
- Forbidden Lands in Port Hope
- Inside Asura Mirror
- Razzachai
- Muggy Plains
- Nibelor
If a spot is no longer accessible, it should be reported, tho.