Dynamic output filters are not called on /
We use sometimes output filter, injected dynamically (with $r->add_output_filter), for example to manage logout or form replay. Recently I used this with the SecureToken Handler.
But it seems we have a little bug. The output filter is always called, except if the URI is '/'. It is maybe a side effect of DocumentIndex? I will try to send a mail to mod_perl users mailing list to get more information.
This is not a critical bug, as our filters are often executed on URI not equal to '/'.