In the out of box model of OBIEE 11g, for a particular dimension table, we do not have data loaded into all the columns. So in the presentation hierarchy, we deleted certain levels that are not required. There are about 18 levels by default and we only needed 2 which are the levels somewhere from 1 to 18. After deleting that other levels, the navigation on the columns is missing.
Say, we needed Level 14 and Level 13. Level 14 has a value 'abc' which has corresponding Level 13 values of 1,2,3,4,5. In answers, when the Presentation Hierarchy is pulled, we are seeing repeated values for abc. When first value of 'abc' is expanded, Level 13 value of '1' is seen. Similarly when the second 'abc' is expanded, '2' is shown.