This happened to me and the user B3N. It seems that if the word "Pokemon" is in the link, uncapitalized, it gets automatically capitalized and the link gets ruined.
That link up here is meant to have a lowercase "p" in "Pokemon". When I post it, the link somehow turns the p -> P and the link is wrong.
This problem seems to be only happening on Pokebase, since it works here and Battle Subway.
♠SpumWack♠ and starpower saw the problem.