Program hangs in CPPREST when http client socket is closed via DLL_THREAD_DETACH

[jvollaroGit]

We are running version "2.10.12.1" of CPPREST. The Windows SDK Version is 8.1 Platform Toolset is Visual Studio 2017 (v141)

Our program connects and sends messages to a web site hosted in AWS (gpcs.3m.com)
On Windows Server 20122 R2 OS, this program hangs. Seee attached stack trace

In the stack trace you can see that ~http_client() happens with Loader Lock (i.e. DLL_THREAD_DTEATCH) This is only an issue with Windows Server 2012 R2. We suggested to client to upgrade OS, but the client says that that OS is still supported by Microsoft.

What can we do. Is it possible to disconnect the http_client prior to a thread detach occurs?