ORA-00600: internal error code, arguments: [ddfnetCFull-4], [Invalid Handle], [], [], [], [], [], [], [], [], [], []

There are bugs related to ORA-600 ddfnetCFull  in 11.2.0.2 release

Bug 12977043: ORA-600 [DDFNETCFULL-4] WHEN USING A SHARED PUBLIC DBLINK

WORKAROUND:
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Use PUBLIC database link instead of SHARED PUBLIC database link