Precisely.... When you put RAM in a motherboard there's a relationship that must work for the RAM and that motherboard to be supported... here's a random example....
Due to the speeds at which DDR3 runs at, the length of the circuit path from the memory controller on the CPU die to the actual RAM chip pin is something like 5". That's all you get. If the RAM chip is 1" and your motherboard is 4" of that path, then everything is fine. There's reasonable lengths allowed for the motherboard, with a certain amount of length left remaining for the RAM.
But what if a given RAM chip is 1.2" for the path on the RAM stick instead of 1"? Then the system won't work.
What about if your motherboard is 4.2" for the circuit instead of 1"? Then the system won't work.
Ok, so you buy motherboard X and drop in Brand A RAM and it works, then drop in Brand B RAM and it doesn't work. The immediate thought is that Brand B RAM must be bad. But, imagine if the motherboard decided to use more than their fair share of that circuit length causing Brand B RAM(which is expecting so much length) to not have it. The motherboard manufacturer is basically to blame for the whole problem, but the RAM manufacturer appears to be the problem to the technician. The technician will wrongly blame the RAM manufacturer when you and I know might know it's the motherboard manufacturer because of their poor engineering design.
That's just one of many examples that apply for RAM alone, and when you have a boundary where Brand A and Brand B meet there's a relationship that must take place. This is why specifications are created. Some specifications give clear-cut limits and tolerances while others do not. If that relationship is not acceptable(regardless of who is actually at fault) then you'll have problems. And neither you nor I can *really* say who is to blame. Just like my example above, it looks like the RAM manufacturer was to blame but in fact it was the motherboard manufacturer.
One good example of a tolerance that isn't so good(but still works) is road lanes. You drive down the street and see the lines separating the road. It's clear that if your tires cross that line unintentionally you might hit someone. You might not, even if they are next to you, because the lane is wider than their vehicle. If you lean to the left side of your lane and the guy to your left leans to the left everything is fine. But, if the guy to your left leans to his right but you both stay in your lanes you could conceivably break your rear view mirrors if they hit. Does this happen? It sure does. It's rare, but it happens.
Unless and until one of the companies actually starts talking about the problem there's no way to know. And like I've said several times, there is almost certainly a legal document that says that neither side can talk about the situation.
At the end of the day there's only one thing that we all(as part of the public) can know for certainty. Don't mix the ram in question with the motherboard in question. Anyone even trying to point fingers just looks ignorant and is trying to blame one side for things they cannot possibly prove.
Accepting the fact that you will not always have all of the information to make an informed decision about everything is the first step to enlightenment in this life. That's why I love conspiracy theorists. They look so stupid when they start talking about things that they cannot possibly know and can never possibly prove. With that I leave you with my favorite anti-conspiracy video....
Moon Hoax Not:
View: http://www.youtube.com/watch?v=sGXTF6bs1IU