Essential Properties not supported in .Mogrts

Hey everyone! Hoping y'all can also help with what I and some others seem to be dealing with... newly restricted functionality when it comes to building .mogrts in AE.

The selling point of "Essential Properties" was that you could define certain controls and properties that you wanted to elevate and access via a single PreComp layer. I understand that this is still functioning correctly (albeit now accessed through the "Properties" panel).

**What seems to have LOST support is the ability to bring those elevated Essential Properties from that single Precomp layer and then add them to a .mogrt via the Essential Graphics panel.**

Regardless of whether I'm selecting those properties in the Properties Panel, or via the Essential Properties twirldown on my PreComp, neither allows me to drag/add to the Essential Graphics panel. It's greyed out, and when an attempt at manuall dragging them in is made, we're met with a new error message:

In many cases you could simply create the .mogrt from within the original Comp (the same place you set up the original propeties). However, there are plenty of times where this is not possible/ideal. For example, I have a bunch of controls rigged up for a .mogrt, and I'd like to add an overall "Scale All" functionality. Because of all the heavy expressions in there,  I can't simply link things to a null without stuff breaking. Instead, I'd rather precomp the whole setup, and add a scale control to the precomp instead. Much easier, and what I used to do... but now can't. 

Does anyone have any intel on whether this is actively being fixed/developed? Any workarounds in the meantime? The change has unfortunately affected the 50+ .mogrt deliverables I owe my client and severly limits what's possible in terms of creating new .mogrts in the future.

Thanks in advance!