Why does Test-EcpConnectivity throws a warning regarding the internal URL property not being set, when in fact it is set?

Hello,

I have setup an Exchange 2013 CU6 environment which contains the following:

1 machine with client access role

3 machine with mailbox role

1 machine with both client access and mailbox server role.

When I run the Test-EcpConnectivity against the machine which has both roles I get the following:  

WARNING: The test couldn't test the internal URL of this virtual directory, because the InternalURL property isn't set.

But when I run "Get-EcpVirtualDirectory|fl" against the same machine, it shows that internal url property is set.

Why is this happening and how can it be solved?