While trying to update/create a custom field (Type=User Story) we are getting an error - Display Name (Category) conflicts after removing all non-alphanumeric characters (Category becomes Category) with another attributeʼs Name (category) - but we are not able to find another custom field called category under User Story, Defect or Portfolio Item types in the API.
This issue is seen because "category" is a pre-defined system name for Rally. It is a hidden system name, so it will not be seen in the Rally API. If this error is seen, please use a different name for the field.
NOTE: This article was created specific to an artifact type of User Story and Field Name of Category, but if this error can be seen on other artifact types as well and it can also be seen for other Field Names that are hidden system names.