I think an API announcement post is a good idea. I'll put one together shortly.
We also mentioned this in the API announcement post for V2 in the "Wildcard certificates" section:
Orders that contain both a base domain and its wildcard equivalent (e.g. *.example.com and example.com) are valid. In that case, there will be two authorization objects in the order for “example.com68”, one of which represents the wildcard validation and one of which represents the base domain validation. Redundant entries will produce an error. For instance, and order containing both *.example.com and www.example.com would produce an error since the wildcard entry makes the latter redundant.
There was a lot of text to process there and we didn't land the change in time to enforce at launch so I can definitely see how this would get missed.