DNSleak fix may or may not work. Some may not even need a dns leak fix. I have no clue why some needed the dns fix or why on some windows, you don't have to fix it.
As for the Classis STUN, I need to run more tests. Using my COD MW3, BO2 etc..steam powered gaming, I did not see that in my wireshark. Send an email to support and schedule a time for teamviewer. Bad thing is that I need legit steam license to install and launch AOE2.
Also, please run a tracert to the STUN ip address while connected to the VPN. See if the traffic goes thru the VPN or direct to STUN server.
Thanks