Are we discussing the apostrophe? It looks like that's giving the link interpreter some problems. FYI, the HTML code for an apostrophe is "ampersand pound 39". The link interpreter seems built to make links parseable by any HTML interpreting browser, so converting a character than can be used in a control sequence makes sense. Showing the converted code rather than the readable character, on the other hand, does look pretty screwy.
As far as I know, reader50's hack was exclusively for the ampersand problem, which is a vBulletin-wide problem.