I can edit (and successfully save) a row as long as the edit 1) doesn't involve changing anything in an obsgroup OR 2) the edit involves adding a new obsgroup where previously there was no data in the obsgroup. I can NOT edit a row if it involves changing data contained in an obsgroup; this results in the long, red error when I attempt to save the changes.
It appears that I cannot delete a row, using the trash can icon, if the popup template contains an obsgroup. It doesn't matter if there is data entered for this obsgroup or not. If the obsgroup is present in the code for the popup form, then I can't delete it. If the popup form only contains obs tags then the trash can icon does work to delete encounters.