Version 4.1.0
It is only a startup warning, the throttling seems to work now. When changing the .rb file I do see the reload message in the log:
08:33:58.264 [INFO ] [port.loader.AbstractScriptFileWatcher] - (Re-)Loading script '/openhab/conf/automation/ruby/throttle_updates_profile.rb'
The message after starting OH4.1:
08:32:44.831 [WARN ] [e.thing.internal.CommunicationManager] - No ProfileFactory found which supports profile 'ruby:throttle_updates' for link 'Lueftung_Airflow -> knx:device:bridge:lueftung_fast_poll:Lueftung_Airflow