To me this kind of sounds like turning a bug into a feature. And that's great. I would not doubt if they were having a problem with phase shift with temp and thought, "Hey, what if we did this intentionally?"

Usually engineers hate the electromagnetic phase shift that comes from temperature change, or worse, temp changed caused physical shifts in phase of the material. One notable example of this is the PTFE dielectric material for coaxial cables which has become notorious for the "teflon knee" in it's temperature vs phase plot.