I think Observium is confusing interfaces.
Just now I reactivated a logical unit in juniper (xe-0/0/1.1698) and Observium thinks is ae0.3550.

In event log:
2016-05-17 19:36:27 ae0.3550 IP address added: 2804:x:x:x:x:x:x:x/126
2016-05-17 19:36:27 ae0.3550 IP address added: 177.x.x.x/30
2016-05-17 19:36:24 ae0.3550 Interface DELETED mark removed

Imagem inline 1

In Juniper:

login@rtr> show interfaces snmp-index 544
  Logical interface xe-0/0/1.1698 (Index 332) (SNMP ifIndex 544)
    Description: VLAN-xxxxxxxxxxxxxxx
    Flags: Up SNMP-Traps 0x0 VLAN-Tag [ 0x8100.1698 ]  Encapsulation: ENET2
    Input packets : 490
    Output packets: 4075
    Protocol inet, MTU: 1500
      Flags: Sendbcast-pkt-to-re, User-MTU, Sample-input
      Addresses, Flags: Is-Preferred Is-Primary
        Destination: 177.x.x.x/30, Local: 177.x.x.x, Broadcast: 177.x.x.x
    Protocol inet6, MTU: 1500
      Flags: User-MTU, Sample-input
      Addresses, Flags: Is-Preferred Is-Primary
        Destination: 2804:x:x:x:x:x:x:x/126, Local: 2804:x:x:x:x:x:x:x


I will send in private the discovery to Mike and Adam.

Thank you!

--
Eduardo Schoedler