Version 2.4.1.Final build from sources.
Simple "project" rule created. Simple pom.xml file data created.
ran windup

Report shows stacktrace:

when-present<#else>when-missing. (These only cover the last step of the expression; to cover the whole expression, use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)?? ---- ---- FTL stack trace ("~" means nesting-related): - Failed at: ${applicationReport.reportFilename} [in template "reports/templates/index.ftl" in macro "applicationReportRenderer" at line 22, column 50] - Reached through: @applicationReportRenderer applicatio... [in template "reports/templates/index.ftl" at line 102, column 17] ---- Java stack trace (for programmers): ---- freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...] at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:131) at freemarker.core.EvalUtil.coerceModelToString(EvalUtil.java:355) at freemarker.core.Expression.evalAndCoerceToString(Expression.java:82) at freemarker.core.DollarVariable.accept(DollarVariable.java:41) at freemarker.core.Environment.visit(Environment.java:324) at freemarker.core.MixedContent.accept(MixedContent.java:54) at freemarker.core.Environment.visitByHiddingParent(Environment.java:345) at freemarker.core.ConditionalBlock.accept(ConditionalBlock.java:48) at freemarker.core.Environment.visit(Environment.java:324) at freemarker.core.Macro$Context.runMacro(Macro.java:184) at freemarker.core.Environment.invoke(Environment.java:701) at freemarker.core.UnifiedCall.accept(UnifiedCall.java:84) at freemarker.core.Environment.visitByHiddingParent(Environment.java:345) at freemarker.core.IteratorBlock$IterationContext.executeNestedBlockInner(IteratorBlock.java:240) at freemarker.core.IteratorBlock$IterationContext.executeNestedBlock(IteratorBlock.java:220) at freemarker.core.IteratorBlock$IterationContext.accept(IteratorBlock.java:194) at freemarker.core.Environment.visitIteratorBlock(Environment.java:572) at freemarker.core.IteratorBlock.acceptWithResult(IteratorBlock.java:78) at freemarker.core.IteratorBlock.accept(IteratorBlock.java:64) at freemarker.core.Environment.visit(Environment.java:324) at freemarker.core.MixedContent.accept(MixedContent.java:54) at freemarker.core.Environment.visit(Environment.java:324) at freemarker.core.Environment.process(Environment.java:302) at freemarker.template.Template.process(Template.java:325) at org.jboss.windup.reporting.freemarker.FreeMarkerIterationOperation.perform(FreeMarkerIterationOperation.java:137) at org.jboss.windup.reporting.rules.rendering.RenderReportRuleProvider$FreeMarkerThreadedRenderer$1.call(RenderReportRuleProvider.java:140) at org.jboss.windup.reporting.rules.rendering.RenderReportRuleProvider$FreeMarkerThreadedRenderer$1.call(RenderReportRuleProvider.java:125) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745)

Attached are files to reproduce issue