Upgrade Database Schema returns ORA-02429 during upgrade of Windchill

An error occurred during execution of SQL executor command SQLCommand[DROP INDEX FVITEM$COMPOSITE].
Nested exception is: java.sql.SQLException: ... (ORA-02429: Index to enforce the unique / primary key is not deleted)
An error occurred during execution of SQL executor command SQLCommand[DROP INDEX ATTRCRITERIONDEF$COMPOSITE12].
Nested exception is: java.sql.SQLException: ORA-02429: cannot drop index used for enforcement of unique/primary key​​​​​​

WARN  [main] com.ptc.windchill.upgrade.dbservices.AbstractUpgradeDBHelper - Not retrying original command: DROP INDEX LCSSKUCOSTSHEET$NMCOMPOSITE2

ERROR [main] com.ptc.windchill.upgrade.statemachine.state.PhaseEventUpgradeState - Upgrade execution failed with the exception:

wt.util.WTException: Message:  Resource bundle/Message key = com.ptc.windchill.upgrade.dbservices.dbservicesResource/4
	at com.ptc.windchill.upgrade.dbservices.AbstractUpgradeDBHelper.executeCommand(AbstractUpgradeDBHelper.java:580) ~[wnc.jar:?]
	at com.ptc.windchill.upgrade.dbservices.AbstractUpgradeDBHelper.executeSql(AbstractUpgradeDBHelper.java:487) ~[wnc.jar:?]
	at com.ptc.windchill.upgrade.dbservices.AbstractUpgradeDBHelper.executeBatchByName(AbstractUpgradeDBHelper.java:949) ~[wnc.jar:?]
	at com.ptc.windchill.upgrade.dbservices.AbstractUpgradeDBHelper.executeBatchAsSchemaOwner(AbstractUpgradeDBHelper.java:880) ~[wnc.jar:?]
	at com.ptc.windchill.upgrade.phases.upgradeschema.UpgradeSchema.dropRemovedIndexes(UpgradeSchema.java:1428) ~[wnc.jar:?]
	at com.ptc.windchill.upgrade.phases.upgradeschema.OracleUpgradeSchemaWorker.execute(OracleUpgradeSchemaWorker.java:84) ~[wnc.jar:?]
	at com.ptc.windchill.upgrade.phases.upgradeschema.UpgradeSchema.execute(UpgradeSchema.java:594) ~[wnc.jar:?]
	at com.ptc.windchill.upgrade.statemachine.state.DefaultRunningUpgradeState.execute(DefaultRunningUpgradeState.java:34) ~[wnc.jar:?]
	at com.ptc.windchill.upgrade.statemachine.state.PhaseEventUpgradeState.execute(PhaseEventUpgradeState.java:55) [wnc.jar:?]
	at com.ptc.windchill.upgrade.statemachine.state.PersistPhaseUpgradeState.execute(PersistPhaseUpgradeState.java:100) [wnc.jar:?]
	at com.ptc.windchill.upgrade.statemachine.state.ReportWriterUpgradeState.execute(ReportWriterUpgradeState.java:76) [wnc.jar:?]
	at com.ptc.windchill.upgrade.statemachine.UpgradeFrameworkStateMachine.run(UpgradeFrameworkStateMachine.java:460) [wnc.jar:?]
	at com.ptc.windchill.upgrade.statemachine.UpgradeFrameworkStateMachine.main_(UpgradeFrameworkStateMachine.java:896) [wnc.jar:?]
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]
	at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
	at java.lang.reflect.Method.invoke(Method.java:566) ~[?:?]
	at com.ptc.windchill.upgrade.statemachine.DynamicLauncher.runUpgradeFrameworkStateMachine(DynamicLauncher.java:76) [wnc.jar:?]
	at com.ptc.windchill.upgrade.statemachine.DynamicLauncher.main(DynamicLauncher.java:43) [wnc.jar:?]
Caused by: java.sql.SQLException: ORA-02429: cannot drop index used for enforcement of unique/primary key

	at oracle.jdbc.driver.T4CTTIoer11.processError(T4CTTIoer11.java:509) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.T4CTTIoer11.processError(T4CTTIoer11.java:461) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.T4C8Oall.processError(T4C8Oall.java:1104) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:553) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:269) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.T4C8Oall.doOALL(T4C8Oall.java:655) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.T4CStatement.doOall8(T4CStatement.java:229) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.T4CStatement.doOall8(T4CStatement.java:41) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.T4CStatement.executeForRows(T4CStatement.java:928) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1205) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.OracleStatement.executeInternal(OracleStatement.java:1823) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.OracleStatement.execute(OracleStatement.java:1778) ~[wc3rdpartylibs.jar:?]
	at oracle.jdbc.driver.OracleStatementWrapper.execute(OracleStatementWrapper.java:303) ~[wc3rdpartylibs.jar:?]
	at wt.tools.sql.SQLCommand.doExecute(SQLCommand.java:187) ~[wnc.jar:?]
	at wt.tools.sql.AbstractCommand.doExecute(AbstractCommand.java:74) ~[wnc.jar:?]
	at wt.tools.sql.AbstractCommand.execute(AbstractCommand.java:56) ~[wnc.jar:?]
	at com.ptc.windchill.upgrade.dbservices.AbstractUpgradeDBHelper.executeCommand(AbstractUpgradeDBHelper.java:562) ~[wnc.jar:?]
	... 18 more