BIG-IP Adding Extraneous Data to to JSON Response

We have a web application that calls a JSON web service. When we run the service through our BIG-IP proxy, we're seeing extraneous data added to the response; examples below (extraneous data in the second code block, it's a "318" and a "0" entry before and after the response). If we refresh the page, the response comes back correctly, without the 318 and 0, and the application works correctly.

The application is an in-house developed .NET web service called by a Silverlight application, all hosted inside SharePoint. BIG-IP runs LTM, APM (for authentication) and ASM.

This never happens going directly to the server. Any ideas how to troubleshoot and correct this issue?

Correct Response:

HTTP/1.1 200 OK
Cache-Control: private
Content-Type: application/json; charset=utf-8
X-SharePointHealthScore: 0
SPClientServiceRequestDuration: 4
SPRequestGuid: 5535d29c-2753-905f-91f4-f074b42f81bf
request-id: 5535d29c-2753-905f-91f4-f074b42f81bf
X-RequestDigest: 0x56BCBF7860570BBBE7FD8F55B0C6C33EF72E4A7C2824B2791751FD59EB05D5EE352C7DAE087CC0B803AC0EE3AB9048090F7AF27704A342ED0ED6141A191AA854,03 Dec 2014 17:17:53 -0000
Persistent-Auth: false
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
X-Content-Type-Options: nosniff
X-MS-InvokeApp: 1; RequireReadOnly
MicrosoftSharePointTeamServices: 15.0.0.4420
Date: Wed, 03 Dec 2014 17:17:52 GMT
Vary: Accept-Encoding
Set-Cookie: MRHSession=27cd8e8cb0ef826ae740fe629786538f; expires=Wed, 03 Dec 2014 17:32:54 GMT; domain=.peakrc.com;path=/;secure
Set-Cookie: LastMRH_Session=27cd8e8cb0ef826ae740fe629786538f; expires=Wed, 03 Dec 2014 17:32:54 GMT; domain=.peakrc.com;path=/;secure
Content-Length: 792

[
{
"SchemaVersion":"14.0.0.0","LibraryVersion":"15.0.4420.1017","ErrorInfo":null,"TraceCorrelationId":"5535d29c-2753-905f-91f4-f074b42f81bf"
},2,{
"IsNull":false
},4,{
"IsNull":false
},5,{
"_ObjectType_":"SP.Web","_ObjectIdentity_":"740c6a0b-85e2-48a0-a494-e0f1759d4aa7:site:3695b296-f745-49f2-86f8-d425d2ae3e4b:web:462e451f-06b3-458a-b2ce-d132b2aa3269","CurrentUser":{
"_ObjectType_":"SP.User","_ObjectIdentity_":"740c6a0b-85e2-48a0-a494-e0f1759d4aa7:site:3695b296-f745-49f2-86f8-d425d2ae3e4b:u:494","Id":494,"IsHiddenInUI":false,"LoginName":"","Title":"","PrincipalType":1,"Email":"","IsSiteAdmin":false,"UserId":{
"_ObjectType_":"SP.UserIdInfo","NameId":"S-1-5-21-362928426-795665308-1658121199-1183","NameIdIssuer":"urn:office:idp:activedirectory"
}
}
}
]

Incorrect Response (see the added 318 and 0):

HTTP/1.1 200 OK
Cache-Control: private
Content-Type: application/json; charset=utf-8
X-SharePointHealthScore: 0
SPClientServiceRequestDuration: 5
SPRequestGuid: 6d35d29c-9757-905f-91f4-fca64d8b042c
request-id: 6d35d29c-9757-905f-91f4-fca64d8b042c
X-RequestDigest: 0xACCF079171C195C571B19F0D6A897746738028BA3DF8462E1A43DAE587D6596358ABA241221B069D7601CDFC463644D78D159E498A657065F493C75DF2E0B343,03 Dec 2014 17:19:32 -0000
Persistent-Auth: false
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
X-Content-Type-Options: nosniff
X-MS-InvokeApp: 1; RequireReadOnly
MicrosoftSharePointTeamServices: 15.0.0.4420
Date: Wed, 03 Dec 2014 17:19:32 GMT
Vary: Accept-Encoding
Set-Cookie: MRHSession=27cd8e8cb0ef826ae740fe629786538f; expires=Wed, 03 Dec 2014 17:34:32 GMT; domain=.peakrc.com;path=/;secure
Set-Cookie: LastMRH_Session=27cd8e8cb0ef826ae740fe629786538f; expires=Wed, 03 Dec 2014 17:34:32 GMT; domain=.peakrc.com;path=/;secure
Content-Length: 804

318 <----- This should not be here
[
{
"SchemaVersion":"14.0.0.0","LibraryVersion":"15.0.4420.1017","ErrorInfo":null,"TraceCorrelationId":"6d35d29c-9757-905f-91f4-fca64d8b042c"
},2,{
"IsNull":false
},4,{
"IsNull":false
},5,{
"_ObjectType_":"SP.Web","_ObjectIdentity_":"740c6a0b-85e2-48a0-a494-e0f1759d4aa7:site:3695b296-f745-49f2-86f8-d425d2ae3e4b:web:462e451f-06b3-458a-b2ce-d132b2aa3269","CurrentUser":{
"_ObjectType_":"SP.User","_ObjectIdentity_":"740c6a0b-85e2-48a0-a494-e0f1759d4aa7:site:3695b296-f745-49f2-86f8-d425d2ae3e4b:u:494","Id":494,"IsHiddenInUI":false,"LoginName":"","Title":"","PrincipalType":1,"Email":"","IsSiteAdmin":false,"UserId":{
"_ObjectType_":"SP.UserIdInfo","NameId":"S-1-5-21-362928426-795665308-1658121199-1183","NameIdIssuer":"urn:office:idp:activedirectory"
}
}
}
]
0 <----- This should not be here