diff --git a/lib/markdownBuilder.js b/lib/markdownBuilder.js
index b4839ba8..25119c70 100644
--- a/lib/markdownBuilder.js
+++ b/lib/markdownBuilder.js
@@ -587,14 +587,14 @@ function build({
       constraints.push(paragraph([link(`https://regexr.com/?expression=${encodeURIComponent(schema[keyword`pattern`])}`, i18n`try regular expression with regexr.com`, text(i18n`try pattern`))]));
     }
     // https://json-schema.org/draft/2019-09/json-schema-validation.html#rfc.section.7.3
-    if (schema.format && formats[schema.format]) {
+    if (schema.format && typeof schema.format === 'string' && formats[schema.format]) {
       constraints.push(paragraph([
         strong(text(formats[keyword([schema.format])].label)),
         text(': '),
         text(formats[schema.format].text),
         link(formats[schema.format].speclink, i18n`check the specification`, text(formats[schema.format].specname)),
       ]));
-    } else if (schema.format) {
+    } else if (schema.format && typeof schema.format === 'string') {
       constraints.push(paragraph([strong(text(i18n`unknown format`)), text(': '), text(i18n`the value of this string must follow the format: `), inlineCode(String(schema.format))]));
     }
 
diff --git a/test/markdownBuilder.test.js b/test/markdownBuilder.test.js
index 17add866..63680ffe 100644
--- a/test/markdownBuilder.test.js
+++ b/test/markdownBuilder.test.js
@@ -92,8 +92,8 @@ describe('Testing Markdown Builder: format', () => {
   });
 
   it('Format Schema looks OK', () => {
-    assertMarkdown(results.properties)
-      .fuzzy`defined in: [Meta](meta-definitions-meta-properties-title.md "https://ns.adobe.com/helix/pipeline/meta#/definitions/meta/properties/title")`;
+    assertMarkdown(results.format)
+      .fuzzy`Formatting used to display the date.`;
   });
 });