I’ve heard starting at a lower HR helps (over at a Maffetone training forum). The drift will still happen, but you will still be in Z2 if you start low enough. Also I have started eating 60-90 minutes into my long runs/hikes and it seems to help as well.
Also I get the same drift, I assume it happens to everyone who is working out right below their AeT. I’ve noticed my rate of perceived exertion feels like upper Z2, but my HR is Z3. Last week I had this problem, and it was compounded by the fact that the steepest part of the entire route was the last two miles. Tomorrow I’m going to start at the low point so the second half is all downhill which should help. And I’m going to try to keep my HR a tad lower too.
I’ve never heard about ADS at a certain age being a lifetime sentence, do you have a link to a thread about that?