Import Fails unless Contact Type Includes Underscores rather than Spaces

If importing a list of contacts which uses the special fields only available to a specific contact type, the contact name must have an underscore rather than a space, e.g., "Mothers Association" must be named "Mothers_Association." Names using a space will import if "Contact Type" is not selected on import menu, however custom fields will be unavailable.

To import custom contact types NOT USING custom fields, a field value of the contact type must be included in the import file where spaces are replaced by underscores.

This appears to be caused because spaces in contact type names are stored as underscores in the database. A temporary fix is to name custom contact types with underscores rather than spaces, or use only a single word in the title, e.g., MothersAssociation.