From my understanding it seems to be operating correct, just not the way you want or expect it to operate. The Guest vlan should be given a different address range so even if they get the voice vlan via lldp-med, they will not have acess to it and will still remain in the guest vlan. All the ports are configured to support the vlan VOICE. When the phone connects initially, it is not enabled for 802.1x so it fails and gets moved to the GUEST vlan. Now it has an IP address it can communicate with the switch. The phone is already authenticated to the network. The fact that it is in the the guest vlan does not prevent the switch from communicating the voice vlan parameters as configured. The switch is doing what it is configured to do.
You can verify this by disabling lldp-med and see what happens. The switch should now stay in the GUEST vlan. You can further verify it by configuring the phone manually with the voice vlan and it should go into the voice vlan when it connects. The set up you have simply assigns the phone to the voice vlan but in a roundabout way. If the objective is to keep the phone in the guest vlan if it fails 802.1x, then disable lld-med options on the phone and it will work.