[bug] If I upvotes a comment and then leave the thread, when I return to that thread the comment no longer has the upvotes arrow marked in colour

To reproduce:

1. Go into a post
2. Upvote a comment. Observe that the up arrow has changed colour
3. Exit the post back to the main page
4. Return to the same post and find the comment. The up arrow will no longer be coloured.