When you add a new ticket attribute that is not associated with any ticket types, the attribute is assumed to be "global" and will show on all ticket types. In order to limit the attribute to specific types, you will need to select the desired types from
the list of types in Admin -> Tickets -> Attributes -> [Attribute] -> Associated Types.
You can also add attributes directly to a type from the Attributes tab in the type details page in Admin -> Tickets -> Types -> [Type]. This will create a new attribute and inherently associate it with that type.