Recently, I am regularly encountering errors of type
\"An unhandled exception of type \'System.StackOverflowException\' occurred in Unknown Module.
StackOverflowException
is usually caused by some method which invokes itself endlessly.
The fact that it occurs after some time makes me even more adamant about it: you're facing infinite recursion.
An extremely simple example of this behavior would be:
void SomeMethod()
{
SomeMethod(); // StackOverflowException
}