Should have posted this up a while back!
Trilogo "QC" sticker cardback.
These black and white QC stickers have shown up on Palitoy ROTJ cards and Trilogos over the years and while there's no official word on them yet (and I've definitely been cautious about getting over excited about them in the past) I've done a bit more digging recently and it does look like they could well be legit quality control examples.
Unlike most of the QC stuff that usually comes from ex-employees, these stickers have all been found on used cardbacks or on MOC with price stickers so they were never archived or anything. Probably just a spot check and put straight back into a shipping case.
I really do hope that at some point in the future some more evidence surfaces to back that up. I've got some more people to speak to about them so fingers crossed.
I have to say a huge thanks to Lee (Palitoy78) for this as he sent it to me for FREE for my focus a little while ago! Very generous of you mate - Thank you!