I'm not sure what caused the issue with blueprint sandboxes - I've reviewed their mods code and mine, and can't really determine how this happened.
I shared a link to a server for uploading save games, do you mind uploading this save if you still have it? Or let me know how to recreate the error?
I think the issue is that my mod marked a machine for upgrade in a blueprint sandbox. It's configured to ignore those entities though so I'm not sure how it got there. I'm wondering if a machine marked for upgrade was copied/cloned into the sandbox in a way that the quality mod missed.