ORA-00600: internal error code After switchover to standby and Switching Back to primary

Introduction

We were observing ORA-00600: internal error code after performing dataguard switchover to standby and switch back to primary.

Details

The scenario here after performing dataguard switchover to standby and switch back to primary application team started complaining and checking database alert log we noticied ORA-00600: internal errors.
ORA-00600: internal error code, arguments: [ktbdchk1: bad dscn], [], [], [], [], [], [], [], [], [], [], []
 
DBVerify on the datafile reported below error,

[oraprd@xla_idx]$ cat xxfah_xla_idx.3176.966695155.log
DBVERIFY: Release 12.1.0.2.0 - Production on Mon Feb 19 07:38:12 2018
Copyright (c) 1982, 2014, Oracle and/or its affiliates.  All rights reserved
DBVERIFY - Verification starting : FILE = +DATAC1/EBSPRD/DATAFILE/xxfah_xla_idx.3176.966695155itl[19] has higher commit scn(0x0968.cd0a7607) than block scn (0x0968.a58866e1)Page 2476267 failed with check code 6056

DBVERIFY - Verification complete

Total Pages Examined         : 4194176 =
Total Pages Processed (Data) : 0
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 4185059
Total Pages Failing   (Index): 1
Total Pages Processed (Other): 4252
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 4865
Total Pages Marked Corrupt   : 0
Total Pages Influx           : 0
Total Pages Encrypted        : 0
Highest block SCN            : 0 (0.0)
[oraprd@xla_idx]$

RMAN cannot detect this corruption.
This actually not Data Corruption.
And this can happen in other databases also.

Solution

We need to put  below work around and apply patch

alter system set "_ktb_debug_flags"=8 scope=both sid='*';
After settting this parameter, it will self heal whenever index is updated.

To avoid future errors, we need to apply patch  22241601 ORA-600 [KDSGRP1] IN ADG AFTER FAILOVER

References

ALERT Bug 22241601 ORA-600 [kdsgrp1] / ORA-1555 / ORA-600 [ktbdchk1: bad dscn] / ORA-600 [2663] due to Invalid Commit SCN in INDEX (Doc ID 1608167.1)
On Standby, DBV Shows Pages Failing With Check Code 6056 (Doc ID 1523623.1)
ORA-1555 Zero Duration/ ORA-600 [ktbdchk1: bad dscn] / ORA-600 [2663] / after Physical Standby switchover (Doc ID 1577824.1)