We have run into an issue over the past 24 hours where links in the body of outbound emails are broken but links in the template we use are not.
The broken links look like this: http://www.example.com/4590dkehoslei4067wsls
The working links look more like this: http://www.example.com/somepage.html?somevariable=1&mkt_tok=asdfghj34567wertyuiocvbnm6789dfgh2345cvb...
The broken links work OK in the email preview but are getting corrupted upon email send.
Not sure if it helps, but I've never been successful using a shortcut within an email.
If by "shortcut" you mean "shortened link" Marketo itself works perfectly fine with such links.
Of course the remote link de-shortener needs to ignore and re-append Marketo's mkt_tok param but that's not Marketo's responsibility (and applies to any additional params).
We've been having a problem today with button links (order, CTA etc) not working. Links within free text boxes work.
Did you every figure out how to fix it?