Incorrect/duplicate result set

Question

In my context index, each document_id is unique. However, when I do a search on one specific document_id, the exact same document is returned to me twice:
select document_id from books
where contains(user_dummy, '402039968');
document_id
402039968
402039968
When I look at the respective partition $I table for this token, I see that:
select token_text, token_type, token_first, token_last, token_count from DR#BOOK_NDX0103$I
where token_text = '402039968';
token_text = 402039968
token_type = 0
token_first = 32035
token_last = 313648
token_count = 2
This double result return does not occur for all documents. Most documents act as expected, and return only once. A correctly working document:
select document_id from books
where contains(user_dummy, '402034806');
document_id
402034806
select token_text, token_type, token_first, token_last, token_count from DR#BOOK_NDX0103$I
where token_text = '402034806';
token_text = 40203480
token_type = 0
token_first = 250153
token_last = 250153
token_count = 1
I do notice a difference in the $I token_count, however do not know what is causing certain documents to be returned twice.
I have also verified that there is a 1:1 relationship in the $K table for this rowid. Does this indicate something was indexed incorrectly? I have run the optimization on this partition. Any ideas/leads would be appreciated!

Answer 1

(if relevant to this situation, Oracle support has not provided a known bug number to me yet)
In DR#BOOK_NDX0103$I, I notice 2 things that do not look correct:
token_text = 402039968
token_type = 0
token_first = 32035
token_last = 313648
token_count = 2
token_first = 32035, however, when I run:
select * from DR#BOOK_NDX0103$K where docid =32035
I get 0 results back, which means that there is no corresponding row in the base table for this docid.
Furthermore, as I indicated before, the token_count, which indicates 2 is incorrect, as there should only be 1 document in this row.
Anybody see this before?