I've applied the Patch but even so just to be sure, I've even installed a
new clean Magento version 188.8.131.52 just to test it.
In that installation I could insert easily also the script in the email
section, so is not about how I've installed the Patch, even in a clean
Magento is happenning.
I went deeper in the code and looks like the new function added to
implement the Zend validation "MaliciusCode", the attributes sent by the
registration Post are not being passed to that function.
Hope that helps.