system.cpu.util item periodically become not-supported status on Windows with the error below.
0x800007D8: A counter with a negative value was detected.
This is related to ZBX-5201 which is for 0x800007D6 (PDH_CALC_NEGATIVE_DENOMINATOR). It's better to ignore if windows returns PDH_CALC_NEGATIVE_VALUE error as well.
Fixed in svn://svn.zabbix.com/branches/dev/ZBX-9233
Available in 2.2.9rc1 r51925, 2.4.4rc1 r51926, 2.5.0 (trunk) r51927.