Documentation at the below link clearly says that "If match is not defined, all queries are considered to match.". All filter modules link to this place from their own pages.

https://mariadb.com/kb/en/mariadb-maxscale-25-mariadb-maxscale-configuration-guide/#standard-regular-expression-settings-for-filters

This is completely wrong, at least for Tee and QLA filters, likely for many (all?) others too. If no match clause is given in the filter's config section, the filter will NEVER match. It order to match all queries, one must specify:

match=/.*/

Unsure if this is a regression or not and if the MaxScale or the docs have to be fixed, but they MUST be aligned. Otherwise we just seem lame and cause confusion and frustration with customers.