Since Zabbix 2.4.x (tried 2.4.3 and 2.4.4) on OpenBSD 5.7-current, system.cpu.util returns 0 all the time. Wrt to ZBX-9067, system.cpu.util returns 0 directly after zabbix agent has been restarted and minutes/hours/days later...doesn't matter.

system.cpu.util = ERROR

zabbix_agentd[6422]: listener #3 [processing request]
zabbix_agentd[6422]: Requested [system.cpu.util[,user]]
zabbix_agentd[6422]: Sending back [0.000000]

Other system.cpu.x requests work

system.cpu.load = OK

zabbix_agentd[6422]: listener #3 [processing request]
zabbix_agentd[6422]: Requested [system.cpu.load[percpu,avg15]]
zabbix_agentd[6422]: Sending back [0.362305]

zabbix_agentd[6422]: listener #3 [processing request]
zabbix_agentd[6422]: Requested [system.cpu.load[percpu,avg1]]
zabbix_agentd[6422]: Sending back [0.395508]

I've tried on differnt machines with Intel Core2 Duo (amd64), Intel Atom (amd64), AMD Geode (i386), Intel Xeon (amd64) without success. A request from the server returns 0.