Nah, it was tainted by some Darksider at some point. Which is dumb.

Okay but it’s still his inner darkness he’s facing there, not the spirit of some long dead Sith. The dude that “definitely not Yoda” killed just imbued the cave with a connection to the Dark Side. That manifests as Luke’s vision of Vader, but it’s still in his head. He’s only facing himself.

Or at least that’s how I interpreted it.

I prefer it being a total psychological thing rather than there being a “Force nexus” tied to a physical location.

Now it’s starting to sound like you guys are saying Luke had a vision just because. Is he schizophrenic? No, of course the Force was involved. I don’t really see why it being strong in certain places is an issue, especially since Yoda implies he knows that Luke will have some sort of experience in the cave. Otherwise he wouldn’t bring him there. The movie itself absolutely implies that the cave itself has a special connection to the Force.