FreeMarker template error (HTML_DEBUG mode; use RETHROW in production!)

For "." left-hand operand: Expected a hash, but this has evaluated to a string (wrapper: f.t.SimpleScalar):
==> firstLevelContent  [in template "wylen_h5/template/pageFirstLevelContent.template.html" at line 25, column 33]

----
FTL stack trace ("~" means nesting-related):
	- Failed at: #assign __wlCanonical = (firstLevelCo...  [in template "wylen_h5/template/pageFirstLevelContent.template.html" at line 25, column 9]
----

Java stack trace (for programmers):
----
freemarker.core.NonHashException: [... Exception message was already printed; see it above ...]
	at freemarker.core.Dot._eval(Dot.java:48)
	at freemarker.core.Expression.eval(Expression.java:101)
	at freemarker.core.DefaultToExpression._eval(DefaultToExpression.java:96)
	at freemarker.core.Expression.eval(Expression.java:101)
	at freemarker.core.ParentheticalExpression._eval(ParentheticalExpression.java:50)
	at freemarker.core.Expression.eval(Expression.java:101)
	at freemarker.core.Assignment.accept(Assignment.java:134)
	at freemarker.core.Environment.visit(Environment.java:335)
	at freemarker.core.Environment.visit(Environment.java:341)
	at freemarker.core.Environment.process(Environment.java:314)
	at com.chestnut.common.staticize.StaticizeService.process(StaticizeService.java:93)
	at com.chestnut.contentcore.publish.staticize.CatalogStaticizeType.doCatalogStaticize(CatalogStaticizeType.java:134)
	at com.chestnut.contentcore.publish.staticize.CatalogStaticizeType.catalogStaticize(CatalogStaticizeType.java:85)
	at com.chestnut.contentcore.publish.staticize.CatalogStaticizeType.catalogStaticize(CatalogStaticizeType.java:76)
	at com.chestnut.contentcore.publish.staticize.CatalogStaticizeType.staticize(CatalogStaticizeType.java:68)
	at com.chestnut.contentcore.publish.strategies.ThreadPoolPublishStrategy.lambda$publish$0(ThreadPoolPublishStrategy.java:44)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:833)