The answer to why she was rejected was that she did not have a PDP in place when the MAPD was written.
Rick
Good catch, Rick! I assumed grandma had a PDP, but going back over the comments, I note that a PDP was never mentioned, so if she did not have a PDP, then she would not be allowed to pick one up through the purchase of a MAPD during the OEP. The fact that no one at CMS pointed this out underscores the mindless bureacracy's lack of interest in serving the public.