Is the field the gets its value from the type 3 entity part of the key of the new entity? If so, then it has to be a qualifying relationship and it has to exist for that record to be created since it is part of the key.
If the field is not part of the key of the new entity, then you need to change the relationship to referencing. This way, the system knows to get the possible values from the type 3 entity and at the same time won't force that field as it is not part of the key.