Steps to reproduce:

1. create fresh database
2. create host
   1. Host name = test
   2. Groups = Zabbix Servers
3. create item
   1. Name = test
   2. Type = Zabbix trapper
   3. Key = test
   4. Type of information = Numeric (unsigned)
4. create trigger
   1. Name = test
   2. expression = {test:test.last()}<>0
5. create action
   1. Name = test
   2. Operation type = Remote command
   3. Target list = Current host
   4. Execute on = Zabbix server
   5. Commands = echo '{ITEM.NAME1}' '{ITEM.KEY1}'
6. start zabbix server
7. zabbix_sender --zabbix-server '127.0.0.1' --host 'test' --key 'test' --value 1
8. open list of problems, open new problem, see "Message/Command"

Result:
Zabbix server:echo '*UNKNOWN*' '*UNKNOWN*'

Expected:
Zabbix server:echo 'test' 'test'