Wrong vl_msg_id set in vl_api_stats_get_poller_delay_t_handler while reporting stats delay currently VL_API_WANT_PER_INTERFACE_SIMPLE_STATS_REPLY and should be VL_API_STATS_GET_POLLER_DELAY_REPLY. That causes problems while retrieving stats delay interval. It looks easy to fix - just fix the id - I will do simple test and send the patch.