If you distribute a hyperlink to a course in Moodle via a Word document for example and the user clicks on the link the log in page appears (if you are not already logged in) and then it takes you to the home page of Moodle. It does not take you directly to the course as it did in prior versions of Moodle.
There is a forum posting on Moodle.org
http://moodle.org/mod/forum/discuss.php?d=77693#p354197

Also forum digest messages that include hyperlinks back to the annoucements are currently bringing up a 404 page not found error. I'm assuming that this is the same issue as it is a hyperlink outside of Moodle but it may well be slightly different as it produces a slightly different result.