Hi James,
Thank you for checking this issue.
We have found out the issue is because of the "dontdisplaylastusername" settings. We have this setting enabled. We now can use the "Reset password " link even from the Lock screen.
Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System
Set the dontdisplaylastusername value to 0
Concerning the support case, we have an active support case for this issue. However, no support engg have reached us so far. I will let you know here if we need any further support on this issue.
Regards,
Murali