Incorrect result of net.tcp.listen check

#zabbix_get -s127.0.0.1 -k net.tcp.listen[22]
5.000000

bash-2.05$ netstat -an|grep '*.22'
.22273 *. 0 0 49152 0 BOUND
.22273 *. 0 0 49152 0 LISTEN
.22 *. 0 0 49152 0 LISTEN
.22273 *. 0 0 49152 0 LISTEN
.22 *. 0 0 49152 0 LISTEN