Connect By statement returning duplicate rows

I'm trying to use a connect by statement to order a table in a hierarchical format.
Each row has an EntityKey and a ParentEK.  Below is just example data to explain what I'm trying to do.

TABLE:
Objkey      ObjId      ParKey
1      Object1      0
2      Object2      1
3      Object3      1
4      Object4      1
5      Object5      2
6      Object6      2
7      Object7      2
8      Object8      3
9      Object9      3

E.g. query:

SELECT   *   FROM objTable
 START WITH ParKey = 0      
  CONNECT BY PRIOR ObjKey= ParKey  

RESULT:
Objkey      ObjId      ParKey
1      Object1      0
2      Object2      1
5      Object5      2
5      Object5      2
5      Object5      2
6      Object6      2
6      Object6      2
6      Object6      2
7      Object7      2
7      Object7      2
7      Object7      2
3      Object3      1
8      Object8      3
8      Object8      3
8      Object8      3
9      Object9      3
9      Object9      3
9      Object9      3
4      Object4      1

These extra rows are not in the database.  I've no idea why the query is repeating them.  I have used a distinct in the query to get the correct results:

SELECT  DISTINCT ObjKey, ObjId, Parkey FROM objTable
 START WITH ParKey = 0      
  CONNECT BY PRIOR ObjKey= ParKey  

Objkey      ObjId      ParKey
1      Object1      0
2      Object2      1
5      Object5      2
6      Object6      2
7      Object7      2
3      Object3      1
8      Object8      3
9      Object9      3
4      Object4      1


But this is not the way I want to approach it.  Mainly because I have a CLOB column that I need to return occasionally and DISTINCT doesnt work with CLOBS, but also because I would like to know what is the right way to do this.
Obviously my table and query are not as simple as above.  The actual query is:

         select * from (
         SELECT Fullwf, Bftype, fType, Bflevel,EntityKey,ParentEK,Customid,Description
                FROM mbrcalcbreakdown  
         START WITH ParentEK = 0  
         CONNECT BY PRIOR EntityKey = ParentEK         
         ORDER BY fullWF
        ) where bftype IN ('Calculation','Reference')

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Really appreciate help on this, has been bugging me for ages.