Connecting to QB 13 with QBSDK 12 gives qb_utils.js error popup - quickbooks

Question

QB 13.0 Enterprise introduced an issue in our environment that did not exist in QB 12.0.
Using QBSDK 12.0, qbXML version 4.0, Windows Server 2008 R2 and a solution developed in python 2.7.3. QB File Doctor does not report any problems and all XMLs are successfully validated by the QB XML Validator.
I had to go thru this post to resolve the LGB file corruption issue after the upgrade:Automatic Login Failure
I have created a test .Net program to replicate the problem, which occurs at random points between BeginSession and EndSession calls:
using QBXMLRP2Lib;
RequestProcessor2 proc = new RequestProcessor2();
proc.OpenConnection2("Test QB", "Test QB", QBXMLRPConnectionType.localQBD);
string ticket = proc.BeginSession("the path to the QB file", QBFileMode.qbFileOpenMultiUser);
proc.EndSession(ticket);
proc.CloseConnection();
A "Script Error" dialog box pops up with:
Line: 46
Char: 8
Error: Unspecified error.
Code: 0
URL: https://qbinproduct.intuit.com/ipd/common/js/qb_utils.js
And the standard two options whether to continue to run the script or not.
Regardless of what is chosen, QB crashes with:
Problem signature:
Problem Event Name: APPCRASH
Application Name: qbw32.exe
Application Version: 23.0.4005.2305
Application Timestamp: 50d6cc51
Fault Module Name: StackHash_5b31
Fault Module Version: 6.1.7601.17725
Fault Module Timestamp: 4ec49b8f
Exception Code: c0000374
Exception Offset: 000ce6c3
OS Version: 6.1.7601.2.1.0.272.7
Locale ID: 1033
Additional Information 1: 5b31
Additional Information 2: 5b3188f7410a3a5d99b8b3c79d62fc31
Additional Information 3: 38e7
Additional Information 4: 38e72e11a56a600df179c0b7bdb3159c
I'll appreciate any solutions or suggestions.