After finding issues with filters etc I decided to test other aspects; Firstly, if I have somehow missed something basic here, I humbly apologise but here is something that needs explanation
I take 2 tracks, they are simply an original and a duplicate except the first track is inverted phase
The second track has an instance of squasher inserted
Squasher has all band turned off ie plugin should be applying nothing
Play 2 tracks and toggle bypass on Squasher
WHY does the track null fine with Squaser off BUT with Squasher on and nothing applied there is obviously a problem??
There is something going on which is why using a normal mult track with parallel compression sound like @#$%^