I’ve been trying to trouble shoot the source of this, but it seems at random, when I activate the Crushstation algo, it immediately starts squealing. Not nice controllable feedback, screeching and squealing. Bypassing the pedal makes it go away, but this has been happening since I set up pre/post routing. I’ve swapped pedal orders around but so far, I can’t make it go away for good.
If your Pre/post connections are not set up right, it can end up fully or partially connecting an output to an input, which will cause feedback. Nothing we can do about it. It will be worse on distortion programs because they add effective compression.
Have a good look at your connections, with help if necessary, and try and spot the feedback path.