Yes, I think this may be a fairly common issue. It probably just takes one badly done alignment adjustment to screw things up - as
@Fifty150hs found as well.
And calling them "shoulders" makes so much sense. I did not know what to call them, but that is clear.
I don't know how much gap is supposed to be on either side of those eccentrics, since my shoulders are all messed up
.
I think due to the spring having things under so much stress, it should be a pretty easy mistake to make - undo the nut a little too much, so the eccentric bolt head and eccentric washer can rise over the shoulders, try to rotate the bolt to do an adjustment, but the spring tension makes this difficult and the head and/or washer can easily slide over the shoulders or mash them away as it seems happened on my car in a few places. For people in most parts of the country, throw in some rust to weaken things and obscure visibility, and of course it is even more likely to be a problem.
I realized as I was writing all that up and posting the photos that I can actually see a lot more in those photos than I ever knew while figuring things out and doing the fix. So for others, this suggests that a quick visual inspection may or may not fully reveal the problems. Taking your own well-lit close-up photos and inspecting them may be needed.
Seems like so many times (like I was back when first getting this car, and right before I solved this problem here) people have cars that drive just fine, but have un-correctable excessive camber, tire wear, and need to do a ton of work just to get an extra degree or so. I'll guess (did not analyze the geometry, this is just based on how much I moved that bolt and how much camber changed) that you get almost one full degree per millimeter of adjustment there.
If they're wanting to try a fix without doing all that work, this might help. And even if they do all the work and still have a problem, this may be it.
I'll also give a strong endorsement here for doing a
DIY string alignment. I did a total of 3x of those throughout this repair process, including a couple of weeks and 50+ miles between the first and last ones. Of course the rear measurements changed and needed adjustment due to this camber adjustment (*). But the front toe alignment needed no adjustment after the first time - confirming repeatability of the measurement procedure. I estimate I got 0.5 mm accuracy or better on the toe measurements, which is about 0.04 degrees or better. Spec is 0.08 to 0.22 degrees of toe in.
The best thing about doing my own alignment was that it actually allowed me to solve this problem. I don't think it would have been possible if I were taking it in for a professional alignment and then trying to figure out what they did as an extra random variable. This episode here was the first time I had touched the rear alignment myself - had previously all been done professionally, and was of course kind of a mystery to me.
(*) - and I also finally put in new Lemfoerder guide links (33-32-6-774-796 ; Lemfoerder 27082 02) when I noticed their boots were cracked while I was adjusting rear toe, and "since I was in there" - but after removing and inspecting more carefully, I can see these original parts with almost 200k miles on them are actually still greased, tight and centered. If it was worth doing, they just needed new boots. Very impressed with the original parts here.