MediaPlatform not opening UDP ports after CommunicationsClient.Build() - Application-Hosted Media on VM

[cbraimiotis]

Environment:

OS: Windows Server (Azure VM)
.NET Framework: 4.7.2
Package: Microsoft.Graph.Communications.Calls.Media v1.2.0-beta.9995
Package: Microsoft.Skype.Bots.Media v1.27.0.2-alpha
Deployment: Standalone VM (not Azure Cloud Services)

Issue:
I'm attempting to deploy the PolicyRecordingBot sample on a Windows VM for Teams compliance recording with application-hosted media. The bot successfully:

Receives incoming call webhooks from Teams
Authenticates requests
Creates IMediaSession objects via Client.CreateMediaSession()
Calls ICall.AnswerAsync(mediaSession)

However, MediaPlatform never opens UDP ports for RTP audio. Specifically:

No UDP ports listening on 8445 (configured InstanceInternalPort)
No UDP ports in range 50000-50019 (expected RTP range)
netstat -ano -p UDP shows no media-related ports
Teams call connects briefly then fails (no audio path established)

Configuration:
csharpvar mediaPlatformSettings = new MediaPlatformSettings
{
MediaPlatformInstanceSettings = new MediaPlatformInstanceSettings
{
CertificateThumbprint = "...",
InstanceInternalPort = 8445,
InstancePublicIPAddress = IPAddress.Parse("x.x.x.x"),
InstancePublicPort = 8445,
ServiceFqdn = "bot.example.com"
},
ApplicationId = "..."
};

builder.SetMediaPlatformSettings(mediaPlatformSettings);
var client = builder.Build(); // No errors thrown

Additionally:
CommunicationsClient builds successfully without exceptions
No MediaPlatform property is accessible via reflection on the client object
Client.CreateMediaSession() returns valid IMediaSession objects with AudioSocket != null
But actual UDP socket binding never occurs
Certificate is valid and bound to port 9442 (signaling works)
NSG rules allow UDP 8445 and 50000-50019

Questions:

Does MediaPlatform require explicit .Start() call that's missing from current SDK versions?
Is there additional native DLL initialization required beyond the NuGet packages?
Are there known compatibility issues with VM deployment (vs Azure Cloud Services)?
How can I verify MediaPlatform internal state or get diagnostic logs?
Is this a known issue for Microsoft.Graph.Communications.Calls.Media: 1.2.0-beta.9995 and Microsoft.Skype.Bots.Media: 1.27.0.2-alpha not working anymore on new deployments?