Network is fine.

Situation:

Open-E (replication,failover working) with two volumes, vol00=100GB and vol01=50GB (all for testing)

Szenario A
failover-target1 - vol00 + iSCSI ID + LUN 0 (100GB)
failover-target2 - vol01 + iSCSI ID + LUN 1 (50GB)

esxi only show a LUN 0 with 50GB
(open-e has the vol01+LUN 1 the 50GB)

Szenario B
failover-target1 - vol00 + iSCSI ID + LUN 0 (100GB) & - vol01 + iSCSI ID + LUN 1 (50GB)

esxi only show a LUN 0 with 100GB

I have tested the failover-target1 with vol00+LUN1 and vol01+LUN2, esxi shows here only a LUN1 (vol00,100GB)