Basic analysis of this shows that some of this error is a consequence of the discussion genre: a baseline coreference model that did not track speakers in the AMRs makes important errors in coreference chains regarding "I" and "you".
such a score is limited in that it was measured over a very small exploration set (40 AMRs), but it provides some preliminary suggestion that the identical underlying AMRs used in the IAA numbers above are not dramatically inflating the inter-annotator agreement.