I am having strange issues with one specific VLAN in a Hyper-V 2012 cluster.
The cluster has 3 servers, each one has a "Management" adapter for management traffic and "VM Data" adapter for virtual machine traffic. Host access is enabled for the Management adapter and disabled for the VM Data adapter. 5 VLANs are enabled for the VM Data adapters with IDs 1,2,3,5 and 7. A virtual machine with the virtual network adapter set to untagged or VLAN IDs 1,2,5 or 7 will work just fine, but there's no network access with VLAN ID 3. I triple-checked everything from switch config, host adapter config, virtual switches and the corresponding enabled VLANs, VM networks and logical networks... no luck. This issue happens on all 3 servers of the cluster.
Server 1+2: HP ProLiant DL380 G7 with HP (rebranded Broadcom) NICs Server 3: Dell PowerEdge 2950 III with Broadcom NetExtreme II NICs
If i directly connect a PC to the switch ports, communicating with VLAN 3 works without a problem.