Logger does not apply filters to MQTT messages

I have an irrigation controller (esp8266 + 8 relays) which is located a bit too far for its poor wifi antenna so it keeps disappearing now and then. As a result, the log is flooded with “became unavailable” and “turned off” (“off” is the state of a relay when the controller is available again).
I am trying to filter these out in the logger as (this is a file included as logger: !include logger.yaml):

default: info
filters:
  homeassistant.components.mqtt:
    - "appletree became unavailable"
    - "pots became unavailable"
    - "appletree turned off"
    - "pots turned off"

“appletree” and “pots” are entity names, clickable in the log. HASS 2023.8.1.
Log entries still appear in the logbook card. What is missing here?