The Lost Lowdown

This episode has fixed one of the paradoxes from the previous episode.
Now that we know that Locke wasn't Locke, but Mr. Loophole, there is no paradox (seemingly) regarding Locke telling Richard what to do and say to Past-Locke.
There still could be a paradox if we're supposed to believe that Mr. Loophole has obtained all of Locke's memories, but if not, the method could have originated with Mr. Loophole.

Though according to the last Official Podcast, the compass is just supposed to be a "neat" little mystery that will never again be addressed, so I'm sure this won't be dealt with either.

I get tired of the countless "neat little mysteries" they throw in just to get people talking and debating, when they know they'll never address it. Stuff like items changing in the Swan, picture frames changing on walls, compasses. They put so much in episodes for people to question then they get upset when viewers question something they didn't mean for them to question. Just stop.