diff --git a/src/core/operations/OffsetChecker.mjs b/src/core/operations/OffsetChecker.mjs
index 0f66e591..2a417e4b 100644
--- a/src/core/operations/OffsetChecker.mjs
+++ b/src/core/operations/OffsetChecker.mjs
@@ -99,7 +99,7 @@ class OffsetChecker extends Operation {
             }
         }
 
-        return outputs.join(sampleDelim);
+        return outputs.join(Utils.escapeHtml(sampleDelim));
     }
 
 }