Hello @Shishagames.
This happens because the game doesn't allow for players to use uppercase letter while the wiki is case sensitive with the pages. So, using your example, the page name is Arcanine Mount (quest), but when linked in chat by a player it becomes arcanine mount (quest). So, the Wiki looks for a page named arcanine mount (quest) and, because it is case sensitive, it does not find one and does not bring the player to the desired page.
The way the chats currently work means there's no way to avoid this, other than sending the links through PMs since those allow for use of capitalization.
However, you are encouraged to suggest your ideas for the game via the Suggestions subforum.
I hope I have clarified the issue enough and if you have further questions, please let me know.