Whenever I click on the favorite link on a topic it redirects me to a 404 page, but the favorite is still saved to the database. You have to hit back several times to return to the original post.
I recently committed a fix for gh#3963... perhaps that resolves this issue?
Please post versions of theme and core nodebb. Sounds like there is a mismatch.
I didn't know if this was intended or not, but I guess it was a bug.