A URQ is a User ReQuest, usually it has a command with it.
If it comes from the Gatekeeper(IP Office) it is reboot or re-register request, if it comes from the endpoint it is a notification to the Gatekeeper, usually a message the phone wants to unregister or is about to reboot.
You can initiate a reboot/re-register request from within sysMon or SSA or with local admin on the phone.
Both slowRRQ and missing keepalives are bad, the messages use UDP so there is no session to terminate by a firewall.
H323 is a complex sessionless protocol, that is why SIP was introduced which prefferred use TCP for Gatkeeper <> endpoint communication.