Using OSPF loopback interface, the device can be added in NMS tool/Ridgeline server without any issues. However, when we configure/enable the syslogs it will not work similar to SNMP traps. Since the source IP differs for SNMP traps and Syslog messages when communicating with NMS tool/Ridgeline server. This is EXOS design limitation.
If we use the physical interface IP, then the syslogs will work has expected.
If we need the Syslog messages to work similar to SNMP traps, then it is a feature request. Please contact local Sales Engineer or GTAC for assistance.