ORA-14048: by Alter index unusable usable : IMPORT

PROBLEM:
when importing schema to database (version 11.2.0.3 linux 64bit) using data pump, Below errors appeared in log.

ORA-39083: Object type CONSTRAINT failed to create with error:
ORA-14048: a partition maintenance operation may not be combined with other operations
Failing sql is:
 ALTER INDEX "TEST"."SYS_C001906177"  UNUSABLE ENABLE

CAUSE:
This is unpublished bug 4919496.  When schema was exported, system generated index was put into unusable state. So export generate the "alter index .... unusable; enable" statement in dump file. this can be proved by generate SQLFILE using import tool. 

SOLUTION:
the error can be ignored during importing. To avoid this error, make system generated index usable when doing export.

reference:
Import Fails With Error ORA-14048 A Partition Maintenance Operation May Not Be Combined With Other Operations [ID 787407.1]