diff --git a/apps/geolibre-desktop/src/lib/share-readiness.ts b/apps/geolibre-desktop/src/lib/share-readiness.ts
index 536d6b0bb4..ede4e55622 100644
--- a/apps/geolibre-desktop/src/lib/share-readiness.ts
+++ b/apps/geolibre-desktop/src/lib/share-readiness.ts
@@ -377,7 +377,12 @@ function carriesOwnData(layer: GeoLibreLayer, embeddedLayerIds?: ReadonlySet<str
   if (layer.geojson) return true;
   const metadata = layer.metadata ?? {};
   if (metadata.embeddedGeoJSON) return true;
-  return isPlainObject((layer.source ?? {}).data);
+  const data = (layer.source ?? {}).data;
+  // An object is an inline GeoJSON payload; an array is the row set a
+  // non-GeoJSON deck.gl visualization (arc, heatmap, hexagon built from a CSV)
+  // keeps in `source.data`. Both travel inside the project file. Only a *string*
+  // `data` is a URL, and that is a reference like any other.
+  return isPlainObject(data) || Array.isArray(data);
 }
 
 /**
@@ -513,8 +518,22 @@ async function probeTarget(
     if (!RETRY_WITH_RANGED_GET.has(head.status)) return outcomeForStatus(head.status);
     // Plenty of object stores and CDNs refuse HEAD while serving GET happily,
     // so a one-byte ranged GET decides it rather than a false "needs a login".
-    const ranged = await request("GET");
-    return outcomeForStatus(ranged.status);
+    try {
+      const ranged = await request("GET");
+      return outcomeForStatus(ranged.status);
+    } catch (error) {
+      const failure = classifyFetchFailure(error);
+      if (failure.kind === "abort") return { status: "unchecked", reason: "aborted" };
+      if (failure.kind === "timeout") return { status: "unchecked", reason: "timeout" };
+      // The HEAD already proved the host answers and lets this origin read the
+      // response, so a rejection here is about the ranged request rather than
+      // the host. `Range` is CORS-safelisted only for a simple byte range, and
+      // an older webview may preflight it and get no matching
+      // `Access-Control-Allow-Headers` back, even though the plain GET a
+      // renderer issues would succeed. Fall back to what HEAD said instead of
+      // reporting a working host as unreachable.
+      return outcomeForStatus(head.status);
+    }
   } catch (error) {
     const failure = classifyFetchFailure(error);
     if (failure.kind === "abort") return { status: "unchecked", reason: "aborted" };
diff --git a/tests/share-readiness.test.ts b/tests/share-readiness.test.ts
index 358d69ffbb..f5a073a02f 100644
--- a/tests/share-readiness.test.ts
+++ b/tests/share-readiness.test.ts
@@ -45,6 +45,23 @@ function fakeFetch(routes: Record<string, number | Error>) {
   return { fn, calls };
 }
 
+/**
+ * Answers HEAD with `headStatus` and rejects the ranged GET, recording both
+ * attempts so a test can prove the retry actually ran.
+ */
+function rejectingRangedGet(headStatus: number) {
+  const attempts: { method?: string; range?: string }[] = [];
+  const fn = (async (_input: RequestInfo | URL, init?: RequestInit) => {
+    attempts.push({
+      method: init?.method,
+      range: (init?.headers as Record<string, string> | undefined)?.Range,
+    });
+    if (init?.method === "HEAD") return new Response(null, { status: headStatus });
+    throw new TypeError("Failed to fetch");
+  }) as unknown as typeof fetch;
+  return { fn, attempts };
+}
+
 describe("isPrivateHostname", () => {
   it("recognizes loopback, private ranges, and reserved suffixes", () => {
     for (const host of [
@@ -194,6 +211,23 @@ describe("collectShareSources", () => {
     assert.equal(refs[0].probeUrl, "https://tiles.example.com/tileset.json");
   });
 
+  it("skips a deck.gl visualization whose rows are inlined as an array", () => {
+    const refs = collectShareSources({
+      layers: [
+        layer({
+          id: "a",
+          name: "Arcs from CSV",
+          type: "deckgl-viz",
+          source: { type: "deckgl-viz", data: [{ lat: 1, lon: 2 }] },
+          // Set when the layer is built from a local file, and not a reference
+          // a recipient needs: the rows travel in `source.data`.
+          sourcePath: "/home/me/flows.csv",
+        }),
+      ],
+    });
+    assert.deepEqual(refs, []);
+  });
+
   it("reports a query-backed layer that names no reference at all", () => {
     const refs = collectShareSources({
       layers: [
@@ -332,6 +366,42 @@ describe("probeShareSources", () => {
     ]);
   });
 
+  it("falls back to the HEAD verdict when only the ranged GET is rejected", async () => {
+    const refs = collectShareSources({
+      layers: [
+        layer({ id: "a", name: "A", type: "cog", source: { url: "https://s3.example.com/a.tif" } }),
+      ],
+    });
+    // HEAD answers 405, so the host is up and readable cross-origin; the ranged
+    // GET is rejected on its own (an older webview preflighting `Range`). That
+    // must not turn a working host into a "blocked" verdict.
+    const { fn, attempts } = rejectingRangedGet(405);
+    const { refs: probed } = await probeShareSources(refs, { fetchImpl: fn });
+    assert.equal(probed[0].status, "reachable");
+    // Without this the test would still pass if the retry were dropped
+    // entirely, since a bare HEAD 405 also reads as reachable.
+    assert.deepEqual(attempts, [
+      { method: "HEAD", range: undefined },
+      { method: "GET", range: "bytes=0-0" },
+    ]);
+  });
+
+  it("keeps a HEAD 403 credentialed when the ranged GET is also rejected", async () => {
+    const refs = collectShareSources({
+      layers: [
+        layer({ id: "a", name: "A", type: "cog", source: { url: "https://s3.example.com/a.tif" } }),
+      ],
+    });
+    const { fn, attempts } = rejectingRangedGet(403);
+    const { refs: probed } = await probeShareSources(refs, { fetchImpl: fn });
+    assert.equal(probed[0].status, "credentialed");
+    assert.equal(probed[0].reason, "auth-required");
+    assert.deepEqual(attempts, [
+      { method: "HEAD", range: undefined },
+      { method: "GET", range: "bytes=0-0" },
+    ]);
+  });
+
   it("reads an opaque browser rejection as browser-blocked", async () => {
     const refs = collectShareSources({
       layers: [