diff --git a/frontend/src/app/site-finder/analysis/[cad]/page.tsx b/frontend/src/app/site-finder/analysis/[cad]/page.tsx
index c3c8a854..6a82c8da 100644
--- a/frontend/src/app/site-finder/analysis/[cad]/page.tsx
+++ b/frontend/src/app/site-finder/analysis/[cad]/page.tsx
@@ -9,10 +9,17 @@ interface PageProps {
   params: Promise<{ cad: string }>;
 }
 
+// Next.js delivers `cad` URL-encoded (":" -> "%3A"); decode once at the page
+// boundary so downstream hooks/components see canonical "66:41:0204016:10"
+// and re-encode exactly once when building API URLs / hrefs (prevents the
+// double-encode that made backend regex reject the cad with HTTP 400).
+// Regression history: PR #351 added this in Client Component; A7 split into
+// Server Component (PR #356) dropped it; this restores in Server boundary.
 export async function generateMetadata({
   params,
 }: PageProps): Promise<Metadata> {
-  const { cad } = await params;
+  const { cad: cadRaw } = await params;
+  const cad = decodeURIComponent(cadRaw);
   return {
     title: `Анализ ${cad} — Site Finder`,
     description: `Анализ инвестиционного участка ${cad}`,
@@ -22,7 +29,8 @@ export async function generateMetadata({
 // ── Page ──────────────────────────────────────────────────────────────────────
 
 export default async function AnalysisPage({ params }: PageProps) {
-  const { cad } = await params;
+  const { cad: cadRaw } = await params;
+  const cad = decodeURIComponent(cadRaw);
 
   return (
     <Suspense