No sound, sound error while editing

Hello, I have a problem with audio. I join videos and I use Volume/gain filter with low volume, I copy filter a lot of times 8all videos with same level) and after 10 or more fragments with the same filter, even if I hear the right volume in preview before placing video in timeline, when I place it the volume goes down like the previous. If I use audio files the result is the same, all audios go down and it’s impossible to increase until the original level

shotcut last version, but it happened fron version 18 until now

Hello, welcome.
Can you attach a screenshot of a project where what you explain happens?
Maybe you have the gain filter placed on the “output” track?
Capture d’écran 2020-09-01 à 10.12.23
Note that you can apply a filter to a track, so all the clips included in that track will be affected.
Capture d’écran 2020-09-01 à 17.22.31

This is taken from a related consultation not many days ago.

Thank you! it’s not a bug, i might have accidentally pressed some key and I added a filter in output window.