I did glance at the video, skipping to 22:25 where she gives a basic explanation of "decoupling" and spends some time on the simple calculation. She then says in a very general sense that looking at decoupling over a large period of time, if she sees "excessive decoupling" she can infer that there is too much fatigue (particularly, she says, when you can't finish a workout). I didn't hear anything I'd think of as "research" nor, frankly, more than a very basic description of what you mean by cardiac drift and one or two of the several factors which contribute to it.
What are you referring to as research in that video, relating to cardiac drift/decoupling? How do you justify, with this video or presumably other research that you're aware of, your use of instantaneous cardiac drift to modify individual training sessions? Apparently the entire rationalization is to train approximately at or near threshold, and in that case why not just train at threshold? Using CD as one of several measures to determine cumulative training stress.