I think i finally have nailed this one.
Hereīs a little song that shows the problem
On the track where the audio is playing from, i have turned the send level all the way down. But itīs still sending with the level from the next track to the delay bus.
https://stash.reaper.fm/oldsb/1158769...aper%20bug.zip
Hope it does the same on your machine, iīve tested on three different ones. Cause it took some time to locate it.
FIXED