I have a test view in the DB:
CREATE OR REPLACE VIEW myschema.v_dummy (
val
) AS
select
123
from
dual;
and get a not recognized statement error:

Importing a test table from the same DB in the same schema works fine.
We have imported several DBs. This is the first one with these problems.
The External Log contains this:
2018-05-25 11:41:09,072 [Thread-91] ERROR MOHViewOracle - MOHViewOracle.generateView():
java.sql.SQLException: ORA-12801: error signaled in parallel query server P002
ORA-06552: PL/SQL: Compilation unit analysis terminated
ORA-06553: PLS-553: character set name is not recognized
at oracle.jdbc.driver.T4CTTIoer11.processError(T4CTTIoer11.java:494)
at oracle.jdbc.driver.T4CTTIoer11.processError(T4CTTIoer11.java:446)
at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:1054)
at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:623)
at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:252)
at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:612)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:226)
at oracle.jdbc.driver.T4CPreparedStatement.doOall8(T4CPreparedStatement.java:59)
at oracle.jdbc.driver.T4CPreparedStatement.executeForRows(T4CPreparedStatement.java:910)
at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:933)
at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1082)
at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3780)
at oracle.jdbc.driver.T4CPreparedStatement.executeInternal(T4CPreparedStatement.java:1343)
at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3822)
at oracle.jdbc.driver.OraclePreparedStatementWrapper.executeQuery(OraclePreparedStatementWrapper.java:1165)
at oracle.dbtools.crest.imports.metadata.oracle.MOHViewOracle.generateView(MOHViewOracle.java:289)
at oracle.dbtools.crest.imports.metadata.oracle.MOHViewOracle.generate(MOHViewOracle.java:203)
at oracle.dbtools.crest.imports.metadata.AbstractDBMExtractionHandler.generateDesign(AbstractDBMExtractionHandler.java:297)
at oracle.dbtools.crest.imports.metadata.oracle.DBMExtractionHandlerOracle.generateDesign(DBMExtractionHandlerOracle.java:263)
at oracle.dbtools.crest.imports.metadata.DBMExtractionController$EmptyRunner.run(DBMExtractionController.java:514)
at java.lang.Thread.run(Thread.java:748)
Caused by: Error : 12801, Position : 0, Sql = SELECT TEXT,TEXT_LENGTH,TEXT_VC,COMMENTS,EDITIONING_VIEW,OID_TEXT,SUPERVIEW_NAME,a.ORIGIN_CON_ID FROM dba_views a,dba_tab_comments b WHERE VIEW_NAME=:1 AND a.OWNER=:2 AND VIEW_NAME=b.TABLE_NAME (+) AND a.OWNER=b.OWNER (+), OriginalSql = SELECT TEXT,TEXT_LENGTH,TEXT_VC,COMMENTS,EDITIONING_VIEW,OID_TEXT,SUPERVIEW_NAME,a.ORIGIN_CON_ID FROM dba_views a,dba_tab_comments b WHERE VIEW_NAME=? AND a.OWNER=? AND VIEW_NAME=b.TABLE_NAME (+) AND a.OWNER=b.OWNER (+), Error Msg = ORA-12801: error signaled in parallel query server P002
ORA-06552: PL/SQL: Compilation unit analysis terminated
ORA-06553: PLS-553: character set name is not recognized
at oracle.jdbc.driver.T4CTTIoer11.processError(T4CTTIoer11.java:498)
... 20 more
SQL Developers loads DDL as

NLS Parasm for that DB are:
NLS_RDBMS_VERSION 12.1.0.2.0
NLS_NCHAR_CONV_EXCP FALSE
NLS_LENGTH_SEMANTICS BYTE
NLS_COMP BINARY
NLS_DUAL_CURRENCY $
NLS_TIMESTAMP_TZ_FORMAT DD-MON-RR HH.MI.SSXFF AM TZR
NLS_TIME_TZ_FORMAT HH.MI.SSXFF AM TZR
NLS_TIMESTAMP_FORMAT DD-MON-RR HH.MI.SSXFF AM
NLS_TIME_FORMAT HH.MI.SSXFF AM
NLS_SORT BINARY
NLS_DATE_LANGUAGE AMERICAN
NLS_DATE_FORMAT DD-MON-RR
NLS_CALENDAR GREGORIAN
NLS_NUMERIC_CHARACTERS .,
NLS_NCHAR_CHARACTERSET AL16UTF16
NLS_CHARACTERSET WE8ISO8859P15
NLS_ISO_CURRENCY AMERICA
NLS_CURRENCY $
NLS_TERRITORY AMERICA
NLS_LANGUAGE AMERICAN
The select from the log fails in sql-tools as well with:
