If I unlike an item it doesn't get removed from the news feed. While I understand it's a cache (I believe so anyway?), shouldn't it remove it anyway as it is no longer relavent (like accidental liking of content).
Otherwise, you could end up with this quite easily:
Ah, so if someone does "Like-Bomb" through the news feed it can't be undone?
How are items removed from the news feed when you permanently remove a hard-delete a post then? I know soft-delete hides it via permission checks. Does it refresh the news feed cache or something?
User caches are never rewritten, but the master data from which the caches are originally built is occasionally rewritten.
You can think of it like this: if someone has already read the news, there is no point in going back and removing that story from their copy of the newspaper, but you can remove it from subsequent publications.
I just went looking and found that it doesn't actually do what I said - it's supposed to remove the entry from the xf_news_feed table (but not the user cache) but in fact it didn't.