Hi David Hodges,
Thank you very much for your contribution. I've looked into the changes you made.
The provided stacktrace does not show an exception in the createFormFields method but int the handleSubmit method of the FormFieldHandler:
The changes you introduce in your PR do not change this method, though.
Could you give more information on why these changes solve your problem? How can this error be reproduced?
Another note: Although adding a test case for this is optional (since we usually don't test exception messages) you could be more assured that the introduced behavior won't change in the future.