Adobe Embed Errors prevent Default Behavior

Basic implementation (including in the SDK demo) throws console errors that are actually affecting customizations:  https://acrobatservices.adobe.com/view-sdk-demo/index.html#/view/FULL_WINDOW/Bodea%20Brochure.pdf

Uncaught (in promise) Error: No callback registered by viewer for GET_FEATURE_FLAG:

There are numerous errors following. As a result, functionality that has worked for over a year (such as programatically open the annotations pane) is now not functioning and I've had to delay shipping a new feature for over a month as a result. Multiple people have posted about this and Adobe has not even suggested they're aware of it.

With no API versioning, users have to just pray Adobe doesn't include breaking changes into the PDF Embed API. Unfortunately, it seems to happen pretty consistently. 

WHEN will this be fixed?

I built on top of this API because it has excellent features. But the instability is so concerning that I never would have used this if I had even the slightest inclination what a headache it would be. Any developers considering this- *stay away* until we the ability to request locked-in API versions.