You probably know this, but just in case:
In Newcomb's problem Omega predicts prior to you choosing. Omega is just really good at this. The chooser doesn't repeatedly observe backwards causality, even if they might be justified in thinking they did.
How is that observably different from backwards causality existing? Perhaps we need to taboo the word "cause".
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
(I plan to make these threads from now on. Downvote if you disapprove. If I miss one, feel free to do it yourself.)