Steps to reproduce:

1. Create SNMP trap item
2. Create trigger which handle item described above with with "and {item.nodata(24h)} = 0" expression to automatically close alert within 24 hours and allow manual close
3. Receive trap
4. Close alert manually 

Result:
Old alarm is resolved but Zabbix generate new alarm after 30 sec for same trap
Expected:
Alarm is resolved and no alarms for old traps

Example trigger: