lol...I guess _SERVER is so important it has to be there twice. hehehe
There was actually a bug in the zend engine that made scripts unset a variable twice to actually take effect, I don't think it related to _SERVER though.
Thank you for your bug report.
This bug has been fixed in our internal code repository. Please note that the problem will not be fixed here until these forums are updated.
With regards,
MyBB Group