After upgrading to SCVMM 2012 R2 (from SCVMM 2012 SP1)
The VLAN ID isn't showing anymore, i know its still there because its showing in Hyper-V Manager.
When you change the VLAN ID it does apply the settings (i can verify in Hyper-V manager) but it still does not show it.
Hyper-V Host: Windows 2008 R2
SCVMM Host: Windows 2012 R2
Using the combination SCVMM 2012 R2 and Hyper-V 2012 R2 there is no issue and it shows the VLAN ID.