Upgrading to Squeeze - and suddenly CGI doesn't work anymore

Before I upgraded from Lenny to Squeeze, all my CGI scripts were working properly. The CGI scripts has been executed by Apache and resulted in rendered webpage. After the upgrade to Squeeze all those CGI scripts stopped been executed but instead started to get displayed as a plain text.

Common to all those CGI scripts is that they have .phtml as suffix, but the bang path/shebang consists of "#!/usr/bin/python". As an example you can have a look at Buildd.Net and its scripts like this one. The section in Apaches config looks like this: 

        <Directory /home/builddnet/unstable/WWW/cgi/>
                Options -Indexes +ExecCGI +FollowSymLinks
                AddHandler cgi-script .cgi .sh .pl .py .phtml
                Order allow,deny
                Allow from all
        </Directory>

So, I would expect that the CGI script handler will get executed when loading a *.phtml file and that the shebang would be honoured. Funny enough: when I rename that script to *.cgi it works.

I haven't figured out yet, what causes this beahviour or what have changed during the upgrade - and how to revert to the old behaviour. So, dear lazyweb, can you give me some hints and pointers?