Office 365 Steaming Subscription Error : One or more subscriptions reside on another client access server

We are trying to subscribe ~2000 rooms with office 365 using Streaming Connections. Very frequently i am getting the following errors, One or more subscriptions reside on another client access server. I understand that this is related to affinity and i am following Microsoft recommendation of using groups and setting the following HTTP Headers. As per microsoft guidelines, we should autodiscover every 12 hours, however i am seeing groups changing after every one hour. Can someone please tell me if anything is wrong in the above traces and why am i repeatedly getting these errors.

I am creating connections per group. Now since groups are changing very frequently and i cannot add subscription to a open connection, i have to wait for 30 minutes till the time the connection for the group to which the failed room belongs. Once connection is disconnected, i add the failed room to the new group connection. 

Also, Following statements are conflicting, one of the link says that x-anchormailbox and connectingSID should be same

Link for the same

however as per msdn, x-anchormailbox should be the first room in the group and connectingSID should be the room that is being processed:

• Include the X-AnchorMailbox header with a value set to the SMTP address of the anchor mailbox user.

• Include the X-PreferServerAffinity header with a value set to true.

• Use the ApplicationImpersonation role (the ExchangeImpersonation type).

MSDN

Which of the two is correct information ?

X-AnchorMailbox,X-PreferServerAffinity,X-BackEndOverrideCookie

Group Name From Auto Discover: https://outlook.office365.com/EWS/Exchange.asmxHKXPR041
Anchor Mailbox:  USSC_CONF_Seminar_Room@condeco.onmicrosoft.com

<Trace Tag="EwsRequestHttpHeaders" Tid="47" Time="2015-01-07 15:12:39Z">
POST /EWS/Exchange.asmx HTTP/1.1
Content-Type: text/xml; charset=utf-8
Accept: text/xml
User-Agent: ExchangeServicesClient/15.00.0913.015
Accept-Encoding: gzip,deflate
X-AnchorMailbox: USSC_CONF_Seminar_Room@condeco.onmicrosoft.com
X-PreferServerAffinity: true</Trace><Trace Tag="EwsRequest" Tid="47" Time="2015-01-07 15:12:39Z" Version="15.00.0913.015"><?xml version="1.0" encoding="utf-8"?><soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:m="http://schemas.microsoft.com/exchange/services/2006/messages" xmlns:t="http://schemas.microsoft.com/exchange/services/2006/types" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"><soap:Header><t:RequestServerVersion Version="Exchange2013" /><t:ExchangeImpersonation><t:ConnectingSID><t:SmtpAddress>USEM_CONF_Q_404@condeco.onmicrosoft.com</t:SmtpAddress></t:ConnectingSID></t:ExchangeImpersonation></soap:Header><soap:Body><m:Subscribe><m:StreamingSubscriptionRequest><t:FolderIds><t:DistinguishedFolderId Id="calendar"><t:Mailbox><t:EmailAddress>USEM_CONF_Q_404@condeco.onmicrosoft.com</t:EmailAddress></t:Mailbox></t:DistinguishedFolderId></t:FolderIds><t:EventTypes><t:EventType>CopiedEvent</t:EventType><t:EventType>CreatedEvent</t:EventType><t:EventType>DeletedEvent</t:EventType><t:EventType>ModifiedEvent</t:EventType><t:EventType>MovedEvent</t:EventType></t:EventTypes></m:StreamingSubscriptionRequest></m:Subscribe></soap:Body></soap:Envelope></Trace><Trace Tag="EwsResponseHttpHeaders" Tid="47" Time="2015-01-07 15:12:42Z">
HTTP/1.1 500 Internal Server Error
Transfer-Encoding: chunked
request-id: 50ffaa1b-4c09-4797-b08d-78f362c7acba
X-CalculatedBETarget: hkxpr04mb166.apcprd04.prod.outlook.com
X-DiagInfo: HKXPR04MB166
X-BEServer: HKXPR04MB166
Cache-Control: private
Content-Type: text/xml; charset=utf-8
Set-Cookie: exchangecookie=936a68304aaf440fa9efaf0ab3619b2b; path=/,X-BackEndCookie2=USSC_CONF_Seminar_Room@condeco.onmicrosoft.com=u56Lnp2ejJqBysmcmpnMnsbSmc6andLLm53I0sadmcjSz8jLmsaeyM+bncebgbyQkZuanJDRkJGSlpyNkIyQmYvRnJCSgc3PzsrSz83Sz8mrzsrFzs7Fy8iBno+cj42bz8vRj42Qm9GQiouTkJCU0ZyQkg==&amp;HKXPR04MB166.apcprd04.prod.outlook.com=rJqNiZqNgbe0p6+tz8uyvc7JydGej5yPjZvPy9GPjZCb0ZCKi5OQkJTRnJCSgc7Gy83Pyc7Oz8qBzc/OytLPztLPyKvOysXNzcXLzg==; expires=Fri, 06-Feb-2015 15:11:47 GMT; path=/EWS; secure; HttpOnly,X-BackEndCookie=USSC_CONF_Seminar_Room@condeco.onmicrosoft.com=u56Lnp2ejJqBysmcmpnMnsbSmc6andLLm53I0sadmcjSz8jLmsaeyM+bncebgbyQkZuanJDRkJGSlpyNkIyQmYvRnJCSgc3PzsrSz83Sz8mrzsrFzs7Fy8g=&amp;HKXPR04MB166.apcprd04.prod.outlook.com=rJqNiZqNgbe0p6+tz8uyvc7JydGej5yPjZvPy9GPjZCb0ZCKi5OQkJTRnJCSgc7Gy83Pyc7Oz8qBzc/OytLPztLPyKvOysXNzcXLzg==; expires=Fri, 06-Feb-2015 15:11:47 GMT; path=/EWS; secure; HttpOnly
Server: Microsoft-IIS/8.0
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
X-FEServer: HKXPR03CA0027
Date: Wed, 07 Jan 2015 15:12:41 GMT</Trace><Trace Tag="EwsResponse" Tid="47" Time="2015-01-07 15:12:43Z" Version="15.00.0913.015"><?xml version="1.0" encoding="utf-8"?><s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"><s:Body><s:Fault><faultcode xmlns:a="http://schemas.microsoft.com/exchange/services/2006/types">a:ErrorProxyRequestNotAllowed</faultcode><faultstring xml:lang="en-US">One or more subscriptions in the request reside on another Client Access server. GetStreamingEvents won't proxy in the event of a batch request.</faultstring><detail><e:ResponseCode xmlns:e="http://schemas.microsoft.com/exchange/services/2006/errors">ErrorProxyRequestNotAllowed</e:ResponseCode><e:Message xmlns:e="http://schemas.microsoft.com/exchange/services/2006/errors">One or more subscriptions in the request reside on another Client Access server. GetStreamingEvents won't proxy in the event of a batch request.</e:Message></detail></s:Fault></s:Body></s:Envelope></Trace>