AF & CA problems with new 70-200 F2.8 Non-IS

Thanks in advance to anyone taking time to read this, and especially to anyone who may be able to respond with helpful insights.

BACK STORY: A couple months back I purchased a Canon 70-200 F2.8 Non-IS lens from B&H. The lens was intended as an upgrade to a 2009 Canon 70-200 F4 IS. Don't want this to become an IS vs Non-IS debate. I never used the IS, and I find myself shooting action in dark conditions pretty frequently, so I wanted to go with the 2.8 (but couldn't afford the 2.8 mkII). I shoot with a Canon 7D.

PROBLEM: Right out of the gate, I felt something may have been wrong with the lens. I shot an outdoor concert event (both day/night conditions), and I missed a LOT of shots due to focus. I'm not used to missing many shots for this reason, so I was quite taken aback. Additionally, many of my shots with moderate (or greater) contrast resulted in what I would consider really bad CA - magenta fringing in front of the focal plane and green fringing behind it. I've only ever encountered this with a few Sigma lenses I've used. It's never been a problem with the Canon lenses I've used (17-55 F2.8, 70-200 F4 IS, several rented 300 F2.8s, rented 135 F2.0, TS-E 24, etc.), so I was quite surprised. Considering the history of this new lens is very good, with excellent reviews, I didn't want to believe there was a problem, so I wondered if my problems - especially the AF issues - were the result of user error. I stuck it out longer than I should have, letting the B&H return period lapse (DANG IT!!). Finally, I tested the lens under controlled conditions and confirmed erratic AF and terrible CA. So contacted Canon and discussed the issues with them, at which point they asked me to send it in for repairs. They worked on it and stated, "Electronic adjustments were carried out on the af assembly. Product functions were confirmed." Being curious as to what they actually did, I called and spoke to a human about it. I was told the AF issued AND the CA issues both would be corrected by the "electronic adjustments."

MORE PROBLEMS: I got the lens back a couple days before needing to use it for another shoot (night football). I micro adjusted the lens under controlled conditions, in the same fashion I have MA'd every other lens I've used. I then tested it in low-light, real-world conditions to confirm function. Seemed to work fine. I did notice CA to a degree I still find surprising as compared to my other Canon lenses, but i needed to shoot that night... Got to the field and began shooting/chimping. After many frustratingly OOF shots, I finally determined that the lens reacts differently depending on the distance of the subject from the lens. I had the MA set at +2 to allow players' eyes to be in focus when targeting the helmet/face mask. This worked fine if the subject was within about 20 yards of me. However, if they were further than this, the lens would back focus by about 15 yards or more!! Long story short, I ended up setting the camera at MA -8 to keep subjects in focus at distances of approximately 30-40 yards away from the lens.

QUESTION: So, after all that, I'm wondering if anyone has any insights on this? Is this down to something I'm doing incorrectly, or is this lens just rubbish? Unless I'm missing something, I don't see how this performance is even close to tolerable for a lens of this caliber.

QUESTION #2: Assuming this copy of the lens is wonky, does anyone have advice on steps to take going forward? I'm really not interested in dancing with Canon on multiple repairs - I just want the lens that I paid for to work! Anyone have experience in similar situations with simply requesting a fresh copy of the lens instead of sending it in for multiple repairs?

You got a bad (very bad) copy IMO ...
You might need to dance with multiple repairs, before Canon accept to switch it (if they do it), but i have no experience of this kind with Canon.
And like you said, i would not want any more this copy.

Back to Canon it goes... Asked about a possible switch with a different, new unit and was curtly told that my warranty only covers repair.

Also, noted that the first repair is warranted for 6 months. I'd had the lens for < 2 months when I sent it in, so the total warranty period for the AF system is now reduced to 8 months from the time of purchase. Seriously. Isn't that sweet?

Finally got it back. 2nd trip took about 2 weeks total, which was a bummer.

On the plus side, it does seem to be AFing correctly, tested in good light and in low light. Still has more CA than I would have expected, based on my 70-200 F4 IS lens...

Onward and upward. Here's hoping it's good going forward!

I'm glad for you
Can you put a picture showing those CA (at 100%) ?
I am intrigued by your "more CA than expected"

Sure - these were taken two days ago (post-repair). Straight from the camera (RAW), with no CA adjustments.

I've only ever experienced this type of CA from my Sigma 85 1.4 (in similar lighting). My old 70-200 F4 IS never did this, under any circumstances...

It's not like I typically shoot in these lighting conditions, if I can help it. But when I CAN'T help it, it's going to suck.

I didn't expect this kind of picture to see those CA

Yes a lot of CA and the green/blue are huge may be worst than the 85 f/1.4 (i have it also) and they are very clear you cannot miss those CA

it's very intriguing

It might be worth to sell it even if you loose a bit of money and buy another one

Thought of that, but can't pawn the problem off on someone else - wouldn't be right, IMO.

Need to use the lens this weekend for a paying job, and then need to decide what to do with it. Canon have already made it clear that the warranty is "repair, not replacement," but I feel it's time to give up on this copy and let me get a new one...

It's back at Canon service. Discovered on another paying shoot that AF is still erratic, and the CA is still bad...