emogrifier: Emogrifier turns $ into %24 unexpectedly

I use merge tags in my email bulletins to customize their content, for example to show the name of the recipient, I use the string $[USER:NAME]$ and then I replace it with the name. If I place the merge tag wrapped in a span or div, there is no inconvenience, but if the merge tag is inside an attribute, let’s say an href, emogrifier turns the ‘$’ symbol to ‘%24’ and ‘[’ to ‘%5B’ respectively. If my original html is <a href="$[LINK:EVENT]$">LINK</a> emogrifier turns it into <a href="%24%5BLINK:EVENT%5D%24">LINK</a>

Any advice to avoid this behavior?