Comment 12 for bug 173043

My configuration is essentially the same as yours (I removed the Alias line from /etc/phpmyadmin/apache.conf and used a symlink instead, but I doubt that affects the bug). What arch are you using -- perhaps the bug only manifests itself on amd64?

I did also find that certain things would cause the bug to disappear temporarily, e.g. I could not reproduce the bug running php5-cgi under gdb.