These syntaxes are broken when called through RC.
I think the problem is quite new, since I haven't heard of any complaints by our users before last update.

{SURVEYURL} and {OPTOUTURL} syntax are not properly converted into usable links in the invitation e-mail.
It works perfectly when sending invitation using limesurvey in a web browser, though.

but when doing this using RC, it won't.
the link remains a text string, not clickable.

Furthermore (but it's basically the same problem), if the email template has something like :
<a href="@@SURVEYURL@@">click here</a>
it appears litteraly like this in the e-mail source code, thus providing just a blank link.