Step to reproduce

After upgrade from 6.2 to 6.4 we have seen that our custom VMware LLD proceprocessing failed.

During some debug we have realized that JSON data field" vm.customattribute: [{}]" has changed to "vm_customattribute: [{}]" after 6.4 upgrade.

Zabbix docs doesn't reflect this change:

https://www.zabbix.com/documentation/current/en/manual/vm_monitoring/discovery_fields

Result:
Error on preprocessing custom Javascript that use wrong vm.customattribute instead of new vm_customattribute