There are things that you have to log in to see, and the mods sometimes move conversations from one place to another, and also, for some reason, whole conversations get reset to a single timestamp.
> for some reason, whole conversations get reset to a single timestamp.
What do you mean?
> and the mods sometimes move conversations from one place to another
This only manipulates the children references though, never the item ID itself. So if you have the item ID of an item (submission, comment, poll, pollItem), it'll be available there as long as moderators don't remove it, which happens very seldom.