Index scan does not return all the data

Hi all;


we have a client that has run into an issue, they have a PK on an id 
column and another unique index on the id and a timestamp. when we run a 
select it selects one of several indexes, in some cases a non unique 
index on a secondary ID, however when we do a pg_dump, or a CREATE TABLE 
x AS select * from this table then we get many many duplicates that 
violate the PK and the unique index.

Thoughts?


Thanks in advance