So I watched this;
https://www.youtube.com/watch?v=P62cSnHY7IA
Kenny summs up (minute 22) adressing if level of folder track is decreased, sends (sent to tracks) keep same messing the mix.
But what about sending an fx to a folder track? I made a quick test (tracks to 2 folders and 1 reverb send) and seems the issue is gone. But I didn't try this in a real mix so unsure what can go wrong.