I pressed the undo/redo key while in the Quantize Effect, and then this happened: https://i.imgur.com/92cUwoj.jpg
The track was playing at the time, if that helps.
There were numerous pages of similar errors (sorry, I was quite out of it at the time and didn’t have the foresight to take more pictures), and when I finished the effect looked totally borked, like so: https://i.imgur.com/GjjMUV0.jpg
Sadly, that’s all I can recall.
I apologize for the sideways picture, and the very minimal documentation I have (I don’t have a project file, sadly), but I was not feeling very well and didn’t feel up to doing more. Hope this still helps though.