'Override to get the reply_to of the parent project.'

@api.model
def message_get_reply_to(self, res_ids, default=None):

    tasks = self.sudo().browse(res_ids)
    project_ids = tasks.mapped('project_id').ids
    aliases = self.env['project.project'].message_get_reply_to(project_ids, default=default)
    return {task.id: aliases.get(task.project_id.id, False) for task in tasks}
