diff --git a/src/islands/maps/MapExplorer.tsx b/src/islands/maps/MapExplorer.tsx
index cbab136..556489e 100644
--- a/src/islands/maps/MapExplorer.tsx
+++ b/src/islands/maps/MapExplorer.tsx
@@ -192,6 +192,22 @@ export default function MapExplorer({ lang = 'en' }: { lang?: Lang }) {
       // never needs its own TileJSON fetch (avoids stale CDN edge responses).
       const styleInput = await fetchResolvedStyle(initialUrl);
       if (cancelled || !containerRef.current) return;
+
+      // Diagnostic: probe one vector tile to verify the proxy returns valid PBF.
+      // Valid gzip-PBF starts with bytes 1f 8b; raw PBF starts with a protobuf tag.
+      // HTML/JSON/text responses (corrupted edge cache) start with ASCII bytes.
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      const omtTiles = (styleInput as any)?.sources?.openmaptiles?.tiles;
+      if (Array.isArray(omtTiles) && omtTiles[0]) {
+        const probeUrl = (omtTiles[0] as string).replace('{z}', '5').replace('{x}', '26').replace('{y}', '16');
+        fetch(probeUrl).then(async r => {
+          const buf = await r.arrayBuffer();
+          const b = new Uint8Array(buf.slice(0, 8));
+          const hex = Array.from(b).map(n => n.toString(16).padStart(2, '0')).join(' ');
+          console.log('[map] tile probe', probeUrl, '→ status:', r.status, 'ct:', r.headers.get('content-type'), 'size:', buf.byteLength, 'bytes:', hex);
+        }).catch(e => console.error('[map] tile probe error:', e));
+      }
+
       // Rewrite every OpenFreeMap URL that MapLibre would fetch on its own
       // (TileJSON, vector/raster tiles, glyphs, sprites) through our /ofm/ proxy.
       // This is the definitive safety net: even if fetchResolvedStyle leaves a
diff --git a/worker/index.js b/worker/index.js
index 38a5df5..5b93e6c 100644
--- a/worker/index.js
+++ b/worker/index.js
@@ -64,9 +64,15 @@ export default {
         return new Response('Method not allowed', { status: 405 });
       }
       const upstream = 'https://tiles.openfreemap.org/' + url.pathname.slice('/ofm/'.length) + url.search;
+      // Fetch WITHOUT cf.cacheEverything so we bypass Cloudflare's edge cache.
+      // The Singapore edge had corrupted cached responses for OFM PBF tile URLs
+      // (HTTP 200 with wrong body), which were being served by the edge cache
+      // when cacheEverything:true was set. Going directly to OFM's origin via
+      // CF backbone avoids those stale entries. The browser's own HTTP cache
+      // (driven by the cache-control header we set below) handles client-side
+      // caching without touching the broken edge entries.
       const res = await fetch(upstream, {
         headers: { 'user-agent': 'goodwebtools-ofm-proxy' },
-        cf: { cacheEverything: true, cacheTtl: 86400 },
       });
       if (!res.ok) {
         return new Response('Upstream OFM fetch failed', { status: res.status || 502 });