If i create a snapshot on ardour, than change to another snapshot and come back to the previous, the loundness is completely different. I have to close ardour and restart the session, than all works normally. I made a video
Thanks Robin. It was the Zl equalizer that suddenly raised the level. After a restart, everything works normally, even with the Zl Eq. Because of interest, I have now installed the older version of the Zl eq, version 0.3.5. This error does not occur with this version.