[Zope] = replaced with == in sendmail!!!!!

[Jay, Dylan]

I have the following inside a sendmail tag

<!--#var URL1-->/completeReg?MagicNumber=<!--#var MagicNumber-->

However in the mail that is sent this comes out as 

http://blah.com/completeReg?MagicNumber==23423434

This is incredibly fustrating and I can find no way around this. Even

<!--#var URL1-->/completeReg?MagicNumber<!--#var "'='"--><!--#var
MagicNumber-->

produces the same result. Whats going on?