That has to do with how spoiler tags are set up on that subreddit: the actual spoiler content is in the title attribute of the link and the href points to /s. T

That has to do with how spoiler tags are set up on that subreddit: the actual spoiler content is in the title attribute of the link and the href points to /s. The CSS for the subreddit uses an attribute selector to find links pointing to /s and styles them appropriately. If you view the posts outside of the context of the subreddit, there's no special CSS, so the link appears normally with some title text that appears on hover.