Please check your customization code. If there is Workflow code overriding the value of the .IsVisible property of the new field, it will not show up; it must be set to TRUE in order for a field to be displayed. Also, remember Workflow code overrides customization done through the ALM Customization GUI which is why you must be careful when adding customization code. If you find some customization code needs to be removed in the future, please check all modules to make sure something like this does not happen.
I hope this solves your problem.