It looks like a concurrency proeblem (a serialization issue) from here. But hard to say...
Are you running multiple worker threads? Is the method where your thread code resides executed more than once?

Or it might be that the worker threads outlive the data objects (grid, or SQL).
For the sake of simplicity I'll give you a minimal example.
The following code MAY or MAY NOT lead to crash, for we can't be sure how long the thread will take to finish.

MyApp::MyMethod()
{

     String text; // String will be destroyed when when MyMethod returns(). 

     Thread().Run([=] {

        // Do someting that takes time.
        text = "hello world";          // This may or may not lead to crash. Because the thread may outlive the text object and MyMethod.   
     });



}

So you'll need to take into consideration all kinds of concurrency problems.

If you can provide a simple example (and a very small dummy database) reproducing the crash, I'll loook into it and try to help.

Regards,

Oblivion.