If these problems are not measurable, then they are lost in trying to better them. So no, I don't believe they are fixing as yet known problems. What they do, and I am friends and professional colleague with Berkeley folks, is engineering excellence. They keep improving the clock. The isolation. Better mechanical build, etc. These are measurable things.
Yes, they all work on things that are measurable. dCS even go so far as to make their own measuring equipment according to their own specifications, when they find other equipment wanting.
But that means that current implementations of digital theory, a theory that as you and others have convinced me is correct, are not perfect yet.
It's all about issues with implementation, not about imaginary problems with the theory itself. Yet problems with implementation are not imaginary.