You deployed UBT to securely tunnel traffic from user desktop PCs connected behind VOIP phones...

The VLAN on which UBT clients are placed is not configured on the switch uplink and traffic from the VoIP phones is being dropped

You tailed to correctly configure a user-defined VRF to support the UBT clients behind the VoIP phones, causing traffic to drop.

Broadcast/multicast packets are copied to both the tunnel and locally, causing duplicate packets and network instability

The UBT client broadcast/multicast packets returned to the same switch port and corrupted the phones IMC table