Error converting xls decision table to decision table in BRMS workbench

I found similar issue here on StackOverflow but that had no answers: Error converting xls decision table to guided decision table BRMS

I have my xls file like this:

After uploading it as Decision Table (Spreadsheet), the table "validates" okay providing proper source (with correct when then blocks) but when I try to "Convert" the table to guided decision table that would generate *.gsdt decision table, I am getting following error on server console:

12:36:32,273 ERROR [org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedDecisionTableFileIndexer] (EJB default - 10) Unable to index 'default://master@tavant/scholarship/src/main/resources/org/crossvale/jbpms/multiplicationtable/MultiplicationTableOfTwo%20(converted%20on%2005-Jan-2018%2012-36-32).gdst'.: java.lang.NullPointerException
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedRuleModelIndexVisitor.getFullyQualifiedClassName(GuidedRuleModelIndexVisitor.java:247)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedRuleModelIndexVisitor.visitSingleFieldConstraint(GuidedRuleModelIndexVisitor.java:214)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedRuleModelIndexVisitor.visit(GuidedRuleModelIndexVisitor.java:84)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedRuleModelIndexVisitor.visitFactPattern(GuidedRuleModelIndexVisitor.java:147)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedRuleModelIndexVisitor.visit(GuidedRuleModelIndexVisitor.java:78)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedRuleModelIndexVisitor.visitRuleModel(GuidedRuleModelIndexVisitor.java:182)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedRuleModelIndexVisitor.visit(GuidedRuleModelIndexVisitor.java:74)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedRuleModelIndexVisitor.visit(GuidedRuleModelIndexVisitor.java:68)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedDecisionTableModelIndexVisitor.visit(GuidedDecisionTableModelIndexVisitor.java:142)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedDecisionTableModelIndexVisitor.visit(GuidedDecisionTableModelIndexVisitor.java:82)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedDecisionTableModelIndexVisitor.visit(GuidedDecisionTableModelIndexVisitor.java:101)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedDecisionTableModelIndexVisitor.visit(GuidedDecisionTableModelIndexVisitor.java:69)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedDecisionTableFileIndexer.toKObject(GuidedDecisionTableFileIndexer.java:74)
at org.drools.workbench.screens.guided.dtable.backend.server.indexing.GuidedDecisionTableFileIndexer$Proxy$_$$_WeldClientProxy.toKObject(Unknown Source)
at org.uberfire.ext.metadata.io.IOServiceIndexedImpl$1$1.run(IOServiceIndexedImpl.java:290)
at org.uberfire.commons.async.SimpleAsyncExecutorService.execute(SimpleAsyncExecutorService.java:137)
at sun.reflect.GeneratedMethodAccessor227.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.jboss.as.ee.component.ManagedReferenceMethodInterceptor.processInvocation(ManagedReferenceMethodInterceptor.java:52)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437)
at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.doMethodInterception(Jsr299BindingsInterceptor.java:82)
at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.processInvocation(Jsr299BindingsInterceptor.java:93)
at org.jboss.as.ee.component.interceptors.UserInterceptorFactory$1.processInvocation(UserInterceptorFactory.java:63)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.invocationmetrics.ExecutionTimeInterceptor.processInvocation(ExecutionTimeInterceptor.java:43)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437)
at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(AbstractEJBRequestScopeActivationInterceptor.java:73)
at org.jboss.as.weld.ejb.EjbRequestScopeActivationInterceptor.processInvocation(EjbRequestScopeActivationInterceptor.java:83)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ee.concurrent.ConcurrentContextInterceptor.processInvocation(ConcurrentContextInterceptor.java:45)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.InitialInterceptor.processInvocation(InitialInterceptor.java:21)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
at org.jboss.as.ee.component.interceptors.ComponentDispatcherInterceptor.processInvocation(ComponentDispatcherInterceptor.java:52)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.singleton.SingletonComponentInstanceAssociationInterceptor.processInvocation(SingletonComponentInstanceAssociationInterceptor.java:53)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInNoTx(CMTTxInterceptor.java:263)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.notSupported(CMTTxInterceptor.java:313)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:237)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.invocationmetrics.WaitTimeInterceptor.processInvocation(WaitTimeInterceptor.java:43)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.security.SecurityContextInterceptor.processInvocation(SecurityContextInterceptor.java:100)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437)
at org.jboss.as.ejb3.concurrency.ContainerManagedConcurrencyInterceptor.processInvocation(ContainerManagedConcurrencyInterceptor.java:110)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.interceptors.ShutDownInterceptorFactory$1.processInvocation(ShutDownInterceptorFactory.java:64)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:66)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.interceptors.AdditionalSetupInterceptor.processInvocation(AdditionalSetupInterceptor.java:54)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.ContextClassLoaderInterceptor.processInvocation(ContextClassLoaderInterceptor.java:64)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:356)
at org.wildfly.security.manager.WildFlySecurityManager.doChecked(WildFlySecurityManager.java:636)
at org.jboss.invocation.AccessCheckingInterceptor.processInvocation(AccessCheckingInterceptor.java:61)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:356)
at org.jboss.invocation.PrivilegedWithCombinerInterceptor.processInvocation(PrivilegedWithCombinerInterceptor.java:80)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
at org.jboss.as.ee.component.ViewService$View.invoke(ViewService.java:195)
at org.jboss.as.ee.component.ViewDescription$1.processInvocation(ViewDescription.java:185)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.interceptors.LogDiagnosticContextRecoveryInterceptor.processInvocation(LogDiagnosticContextRecoveryInterceptor.java:82)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.interceptors.AsyncFutureInterceptorFactory$1$2.runInvocation(AsyncFutureInterceptorFactory.java:101)
at org.jboss.as.ejb3.component.interceptors.AsyncInvocationTask.run(AsyncInvocationTask.java:74)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
at org.jboss.threads.JBossThread.run(JBossThread.java:320)

Refer following workbench screenshot for reference:

Note: After uploading the xls file, the source section the uploaded decision table shows the rules correctly but once I try to convert it, the rules lose then part of the code.

Any idea that can guide me to the right direction would be appreciated. Thanks in advance!

This is a bug as of now. I spoke with several Red Hat folks directly and these might be fixed in future versions. I am going to raise a feature request soon.