Teester
I think the key thing in this case is that it is a boundary between EDs.  In numerous cases, townlands with EDs splitting them have been split into 2 separate townlands on both GSGS3906 and OSi Opendata. e.g.  Agall in Offaly: http://maps.openstreetmap.ie/os_opendata.html?zoom=15&lat=53.25794&lon=-7.59429&layers=0BTFTFTFFFF or Killashee in Kildare: http://maps.openstreetmap.ie/os_opendata.html?zoom=15&lat=53.25794&lon=-7.59429&layers=0BTFTFTFFFF

The only places that this doesn't happen is in urban districts, where the urban EDs will cross townlands on a whim (see Naas Urban ED to the north of the Killashee example)

Whether townlands should be split or not in the case of EDs is a larger question, probably better suited for the mailing list since it affects so many townlands across the country.  While CPs and Baronies are obsolete boundaries from an administrative point of view, EDs and townlands remain official administrative entities in Ireland and I'm not sure that decisions taken in regard to those boundaries should necessarily be assumed to be valid in the case of EDs without consensus first.