Delossifier works pretty great for the most part, but sometimes the spectral hole filler can add really weird, noisy, and unpleasant harmonics / distortion, when it shouldn't. It sounds like the kind of distortion you'd get from a broken speaker or bad tube.
Here's an example:
This issue has been present for as far back as I could test. In this case I'm using 9.01 final.
Here's the track:
https://drive.google.com/open?id=1GDd7z ... O9Bov9HgYT
Stereo Tool settings file attached.
The settings really don't matter though, because all you have to do is turn Delossifier on at the defaults. The attached settings though with AutoEQ, Absolute Highs, etc. will certainly make the distortion more audible.
I want to point out, there is something about certain tracks that causes this to happen. I think it's tracks that have spectral qualities like the above, where it makes the spectral hole algorithm "think" that there's a hole due to lossy compression when it's actually supposed to be the way it is. I only have this happen to a small number of tracks.