Imfor Umman: If you, DPR, are publishing this for the sake of transparency, which is a noble reason, then I beg you, follow up on that cause. Call Canon and tell them:
1. You've designed a great little camera but are producing it with a production-flawed lens. This is what we will publish. Unless...
2. We go out and buy at least 12 of these cameras, on our own, from different stores, locations, even countries, while you reimburse us for those costs. We will then test those cameras to find out whether it was just a early batch problem or something found in regular examples people will be buying.
3. If you don't cooperate as asked, we will publish the results as we have them now: three cameras with the same fault is just not a statistical anomaly, it's reality. This is your only chance.
If they go for it, great, if not, it is your right -- no, your duty -- to believe what three cameras are showing, one good cameras cannot disprove that picture.
Good idea and then give away the 12 cameras to dpreview readers as a co-promotion with Canon. Even if they do exhibit this minor defect, I'm sure you'd have a lot of very happy readers to get one for free!