Cryptographic Checksum Mismatch Error on EM 13.4 Repository DB Alert Log

Following error was observed in the EM (EM 13.4) repository database alert log.

NI cryptographic checksum mismatch error: 12599.

  VERSION INFORMATION:
        TNS for Linux: Version 19.0.0.0.0 - Production
        Oracle Bequeath NT Protocol Adapter for Linux: Version 19.0.0.0.0 - Production
        TCP/IP NT Protocol Adapter for Linux: Version 19.0.0.0.0 - Production
  Version 19.6.0.0.0
  Time: 24-MAR-2020 13:54:03
  Tracing not turned on.
  Tns error struct:
    ns main err code: 12599

TNS-12599: TNS:cryptographic checksum mismatch
    ns secondary err code: 12656
    nt main err code: 0
    nt secondary err code: 0
    nt OS err code: 0
2020-03-24T13:54:03.565478+00:00

The sqlnet.ora in the Oracle home had the following parameters set which are related to encrypting while in transit.

SQLNET.ENCRYPTION_SERVER=required
SQLNET.ENCRYPTION_CLIENT=required

SQLNET.ENCRYPTION_TYPES_SERVER=aes256
SQLNET.ENCRYPTION_TYPES_CLIENT=aes256

SQLNET.CRYPTO_CHECKSUM_SERVER=required
SQLNET.CRYPTO_CHECKSUM_TYPES_SERVER=(SHA1)

SQLNET.CRYPTO_CHECKSUM_CLIENT=required
SQLNET.CRYPTO_CHECKSUM_TYPES_CLIENT=(SHA1)

The error is differnt to when there's no common encryption or checksum between client and server. Following shows the output for such a case (output is same whether the mismatch is on encryption or checksum).

Fatal NI connect error 12650, connecting to:
 (ADDRESS=(PROTOCOL=tcp)(HOST=10.17.16.19)(PORT=62960))

  VERSION INFORMATION:
        TNS for Linux: Version 19.0.0.0.0 - Production
        Oracle Bequeath NT Protocol Adapter for Linux: Version 19.0.0.0.0 - Production
        TCP/IP NT Protocol Adapter for Linux: Version 19.0.0.0.0 - Production
  Version 19.8.0.0.0
  Time: 17-SEP-2020 14:46:49
  Tracing not turned on.
  Tns error struct:
    ns main err code: 12650

TNS-12650: No common encryption or data integrity algorithm
    ns secondary err code: 0
    nt main err code: 0
    nt secondary err code: 0
    nt OS err code: 0
opiodr aborting process unknown ospid (6796) as a result of ORA-609
2020-09-17T14:46:50.321241+05:30

MOS note 2332486.1 this is due to bug 26933408. As a solution it offers two patches, 26933408 for OMS (server side) and 31840839 for agent (client side). After the patches were applied the error message did appear any more.

Related Metalink Notes
TNS-12599: TNS:cryptographic Checksum Mismatch in alert.log after enabling of encryption on the server side [ID 1927120.1]
EM 13c: Enterprise Manager 13c Cloud Control Target Database Repeating Alert Log Errors: TNS-12599: TNS:cryptographic Checksum Mismatch [ID 2332486.1]