I would like to bump this report up, but also provide more data on the matter.
I first assumed the problem is only present in HD as it probably is, and from my quick look into it, all of the aforementioned units lack facefx data that most other units have in HD. I don’t think this is the right place to explain what FaceFX is or even why FAFX is a part of the v1000 of MDX, but it would explain why it’s exactly those models that don’t work with Rifleman sounds (Riflemen have FAFX) and also why the soundsets of those units work interchangeably.
My current assumption can be summed up as: “Sounds bound to FAFX animations won’t play on units without them” which also tells us what to look out for in the future.