Note 1413928 - Index corruption wrong results after rebuild index ONLINE

Other terms
Wrong Results, Corruption (Index), ORA-08102 / ORA-01499,
ORA-00600 [kdsgrp1], ORA-00600 [qertbFetchByRowID], ora-01452

Reason and Prerequisites
Wrong results or the next errors can be produced by SQL statements:

ORA-8102 by a delete/update
ORA-1499 by "analyze table validate structure cascade"
ORA-600 [kdsgrp1]
ORA-600 [qertbFetchByRowID]

This is Oracle Bug 7329252 which is fixed in Oracle release 10.2.0.5.

Solution
Install the relevant patch for your platform.
You can find this on SAP Service Marketplace in the software center