diff --git a/frontend/src/components/StructuredLogViewer.tsx b/frontend/src/components/StructuredLogViewer.tsx
index 0e24bdfa..ec511119 100644
--- a/frontend/src/components/StructuredLogViewer.tsx
+++ b/frontend/src/components/StructuredLogViewer.tsx
@@ -43,8 +43,7 @@ function formatTs(iso: string | null): string {
   const hh = String(d.getHours()).padStart(2, '0');
   const mm = String(d.getMinutes()).padStart(2, '0');
   const ss = String(d.getSeconds()).padStart(2, '0');
-  const ms = String(d.getMilliseconds()).padStart(3, '0');
-  return `${hh}:${mm}:${ss}.${ms}`;
+  return `${hh}:${mm}:${ss}`;
 }
 
 export default function StructuredLogViewer({ stackName }: StructuredLogViewerProps) {