Steps to reproduce:

1. create item proc.num for some process
2. run with zabbix-agent2
3. repeat monitornig

Result:
**

proc.num sometimes return 0. Here's 2 days graph before upgrade from 5.0.12 to 5.0.13 for proc.num[redis]. The actual process is running without stopped for several months.

Expected: 

proc.num return correct number of process matching condition specified in the item like before.

reference change: ZBXNEXT-6596