diff --git a/pkilint/document.py b/pkilint/document.py
index e81f177..370fa0a 100644
--- a/pkilint/document.py
+++ b/pkilint/document.py
@@ -320,7 +320,7 @@ def decode_substrate(source_document: Document, substrate: bytes,
 
             raise SubstrateDecodingFailedError(
                 source_document, pdu_instance, parent_node,
-                f'{len(rest)} unexpected octet(s) following {type_name} TLV: "{rest_hex}"'
+                f'{len(rest)} unexpected octet(s) following "{type_name}" TLV: "{rest_hex}"'
             )
 
         try:
diff --git a/tests/integration_certificate/pkix/trailing_octet_in_ku_value.crttest b/tests/integration_certificate/pkix/trailing_octet_in_ku_value.crttest
index 45820a2..535bf95 100644
--- a/tests/integration_certificate/pkix/trailing_octet_in_ku_value.crttest
+++ b/tests/integration_certificate/pkix/trailing_octet_in_ku_value.crttest
@@ -39,5 +39,5 @@ ZF6TmlI5DUrO
 -----END CERTIFICATE-----
 
 node_path,validator,severity,code,message
-certificate.tbsCertificate.extensions.0,ExtensionsDecodingValidator,FATAL,itu.invalid_asn1_syntax,"ASN.1 decoding failure occurred at ""certificate.tbsCertificate.extensions.0.extnValue"" with schema ""KeyUsage"" corresponding to type OID 2.5.29.15: 1 unexpected octet(s) following KeyUsage TLV: ""41"""
+certificate.tbsCertificate.extensions.0,ExtensionsDecodingValidator,FATAL,itu.invalid_asn1_syntax,"ASN.1 decoding failure occurred at ""certificate.tbsCertificate.extensions.0.extnValue"" with schema ""KeyUsage"" corresponding to type OID 2.5.29.15: 1 unexpected octet(s) following ""KeyUsage"" TLV: ""41"""
 certificate,SubjectKeyIdentifierPresenceValidator,WARNING,pkix.certificate_skid_end_entity_missing,
\ No newline at end of file