Steps to reproduce:

1. Create a new action for auto registration like this:
   • Condition: Host metadata like linux
   • Operation: Add host
   • Operation: Send message
2. Configure in zabbix_agentd.conf:
   • HostMetadata=linux
3. Restart zabbix agent

Result:
Host gets added but no message is sent.
Expected:
Host added and message sent.

Notes:

• If metadata details are removed from action and from agent, host gets added and message is properly sent.
• Issue seems to have started after updating zabbix-server from 3.2.8 to 3.2.11.