iOS 9.3 VPN On Demand ignores RequiredDNSServers

We have an app which works well on iOS 9.2, it use the feature "RequiredDNSServers" of VPN On Demand. But when upgrade to 9.3 (9.3 all versions, including 9.3.2 beta 4), VPN On Demand just ignore "RequiredDNSServers". We submiited a bug to apple and got response that "There is nothing Developer Technical Support can help, you should connect general VPN support which is supported by AppleCare". I am using the same mobile configuration on iOS 9.2 and iOS 9.3 but get totally opposite result. But the document didn't indicate they have made API change. As far as I know, it should be a bug instead of a isse AppleCare can handle.

I'm asking this question hoping to get some advice which apple department I should asking for help? Our app really heavily depends on this API.

Here is some code snippet of our mobile configuation.

Expected result:

When loading google.com, it should first check 8.8.8.8 for DNS result.

Actual result:

It will not request 8.8.8.8 for DNS result and will start VPN connection immediately.

<key>OnDemandEnabled</key> 
   <integer>1</integer> 
  <key>OnDemandRules</key> 
   <array> 
     <dict> 
       <key>Action</key> 
         <string>EvaluateConnection</string> 
       <key>InterfaceTypeMatch</key> 
        <string>Wifi</string> 
       <key>ActionParameters</key> 
         <array> 
           <dict> 
             <key>Domains</key> 
               <array> 
                 <string>www.google.com</string> 
               </array> 
             <key>RequiredDNSServers</key> 
               <array> 
                 <string>8.8.8.8</string> 
               </array>                
             <key>DomainAction</key> 
               <string>ConnectIfNeeded</string> 
           </dict> 
         </array> 
     </dict> 
   </array>