same ScriptResource,axd loaded twice - asp.net

Question

Good Morning,
We have an existing application that is stable and error free on a Windows Server 2008R2 with IIS 7.5 / .NET 4.5.
We are planning a move to Windows Server 2012R2 with IIS 8.5 / .NET 4.5 and are now encountered the problem that the application (identical binaries / configuration) are indeed injected two ScriptResource.axd files, but both contain the same content (different URLs).
Because of this, the MicrosoftAjaxWebforms.js, which provides "Sys.WebForms" is missing and i'm getting the Error
Unable to get property 'PageRequestManager' of undefined or null reference
The problem is browser Independent on two independent virtual machines.
The application runs in classic mode, the web.config does not contain the < xhtmlConformance > tag.
There are all the latest server updates.
All other functionalities of the application are working properly.
I hope some of you encountered the same Problem and know the solution.
Greetings, Verni
EDITH:
Snippet of web.config (system.web section)
<system.web>
<httpRuntime requestValidationMode="2.0" requestPathInvalidCharacters="" targetFramework="4.5" enableVersionHeader="false" />
<sessionState timeout="30" mode="StateServer" stateConnectionString="tcpip=...:42424" />
<httpModules>
<add name="LinkPartnerModule" type="....LinkPartnerModule, ..." />
<add name="RedirectModule" type="....RedirectModule, ..." />
<add name="ScriptCompressorModule" type="ScriptCompressorModule, ..." />
</httpModules>
<httpHandlers>
<remove verb="*" path="scriptresource.axd"/> // added from StackOverflow
<add verb="*" path="*js.axd" type="ScriptCompressorHandler" />
</httpHandlers>
<compilation debug="false" defaultLanguage="c#" targetFramework="4.5">
<assemblies>
<add assembly="System.Web.Abstractions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
<add assembly="System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Data.Services.Client, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Data.Services.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<add assembly="System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A" />
<add assembly="System.Speech, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
</assemblies>
</compilation>
<globalization culture="de-DE" enableClientBasedCulture="true" fileEncoding="utf-8" uiCulture="de" />
<pages compilationMode="Auto" styleSheetTheme="*" validateRequest="false" enableEventValidation="false" controlRenderingCompatibilityVersion="3.5" enableViewState="true" clientIDMode="AutoID">
</system.web>
<system.web.extensions>
<scripting>
<scriptResourceHandler enableCompression="true" enableCaching="true" />
</scripting>
</system.web.extensions>

Answer 1

We had this issue as well for an application running in classic mode. The issue that time turned out to be multiple httphandlers registered for the .axd extension.
If you in your web.config make sure to remove any .axd handler before adding them it might resolve your issue.
Something like:
<remove verb="*" path="scriptresource.axd"/>
Edit:
When looking at your web.config I'm pretty sure the problem is related to the scriptcompressorhandler and module. As you stated this only happens using HTTPS and I suspect that what happens is that the module still runs over HTTPS but the handler does not. This means that the module sends the compressed version over to the regular scriptresource handler and a new copy of the script is outputted.
The solution would be to either activate scriptcompressorhandler over HTTPS as well or make sure the module is not run over HTTPS.

Answer 2

I fixed the Problem.
The reason was an misconfigured ARR (Application Request Router),
where SSL-Offloading was active.
The main reason of misconfiguration was the "function" that activates SSL-Offloading if no URL-Rewrite Rule is there with name like 'ARR_farmName_loadbalance_SSL'.
If this Rule will be deleted, the manager activates SSL-Offloading automatically.
Thanks to Robban, who brought me to HTTPS / SSL.