Squasher won't activate

Problem with squasher.
If I open a new project squasher functions perfectly as an insert.
when I open projects which previously functioned perfectly with squasher the insert slot shows squasher but I cannot switch it on. Opening a new instance shows the correct screen however the dropdown of presets is not there. However the arrows for show next program do function. This is in several projects which all functioned previously with squasher.

Ok discovered a bit more. If I switch off constraint delay compensation Squasher kicks back in. Turn constraint on and squasher is switched off.
So I guess my new question is how do I have both on.

And your answer is , you can’t . Delay compensation is there for a reason so i always build the track with latency intensive plugins and then render . sames time and Cpu processing power