diff --git a/lib/graph/question-formulator.js b/lib/graph/question-formulator.js
index 355751d..21b7125 100644
--- a/lib/graph/question-formulator.js
+++ b/lib/graph/question-formulator.js
@@ -102,6 +102,8 @@ function extractMeaning(node) {
   const strippedDescription = stripTrailingPunctuation(description)
     .replace(/^uncertainty regarding\s+/i, "")
     .replace(/^uncertainty about\s+/i, "")
+    .replace(/^unknown\s+/i, "")
+    .replace(/^uncertain\s+/i, "")
     .trim();
 
   const extractWhetherProposition = (text) => {
diff --git a/tests/graph/question-formulator.test.js b/tests/graph/question-formulator.test.js
index 8a4d85c..fbc90ac 100644
--- a/tests/graph/question-formulator.test.js
+++ b/tests/graph/question-formulator.test.js
@@ -795,4 +795,179 @@ describe("formulateQuestion", () => {
       "What would clarify magnitude and nature of cash outflows (operating expenses) in this situation?",
     );
   });
+
+  // ── 60B.28: uncertainty-prefix coverage ────────────────────────────
+
+  it("60B.27 regression: 'Unknown whether...' preserves full proposition", () => {
+    const unknown = makeNode({
+      id: "unc-60b27",
+      label: "Prospective enterprise customer signing likelihood",
+      description:
+        "Unknown whether one prospective enterprise customer will sign if we launch this year, so that the remaining £700k of the expected £1.2M annual revenue is realized.",
+      kind: "unknown",
+      status: "unknown",
+      confidence: "medium",
+    });
+
+    const graph = makeGraphFor(unknown, {
+      centralStatement:
+        "We need to decide which launch timing option provides superior net value.",
+    });
+
+    const result = formulateQuestion({ node: unknown, graph });
+
+    expect(result.question).toBe(
+      "What evidence would clarify whether one prospective enterprise customer will sign if we launch this year?",
+    );
+    // Rationale must NOT leak into the final question
+    expect(result.question).not.toContain("£700k");
+    expect(result.question).not.toContain("£1.2M");
+    expect(result.question.toLowerCase()).not.toContain("annual revenue");
+  });
+
+  it("'Uncertain whether...' exposes the full proposition with evidence framing", () => {
+    const unknown = makeNode({
+      id: "unc-uncertain",
+      label: "Supplier renewal uncertainty",
+      description:
+        "Uncertain whether the supplier will renew, because the contract is still under review.",
+      kind: "unknown",
+      status: "unknown",
+      confidence: "medium",
+    });
+
+    const result = formulateQuestion({
+      node: unknown,
+      graph: makeGraphFor(unknown),
+    });
+
+    expect(result.question).toBe(
+      "What evidence would clarify whether the supplier will renew?",
+    );
+  });
+
+  it("bare 'Whether...' remains unchanged (existing behaviour)", () => {
+    const unknown = makeNode({
+      id: "unc-bare-whether",
+      label: "Supplier renewal likelihood",
+      description: "Whether the supplier will renew the contract.",
+      kind: "unknown",
+      status: "unknown",
+      confidence: "medium",
+    });
+
+    const result = formulateQuestion({
+      node: unknown,
+      graph: makeGraphFor(unknown),
+    });
+
+    expect(result.question).toBe(
+      "What evidence would clarify whether the supplier will renew the contract?",
+    );
+  });
+
+  it("'Uncertainty about whether...' remains unchanged (existing behaviour)", () => {
+    const unknown = makeNode({
+      id: "unc-about",
+      label: "Customer renewal likelihood",
+      description:
+        "Uncertainty about whether the customer will renew next year, because that affects the decision.",
+      kind: "unknown",
+      status: "unknown",
+      confidence: "medium",
+    });
+
+    const result = formulateQuestion({
+      node: unknown,
+      graph: makeGraphFor(unknown),
+    });
+
+    expect(result.question.toLowerCase()).toContain(
+      "whether the customer will renew next year",
+    );
+  });
+
+  it("'Uncertainty regarding whether...' remains unchanged (existing behaviour)", () => {
+    const unknown = makeNode({
+      id: "unc-regarding",
+      label: "Client retention uncertainty",
+      description:
+        "Uncertainty regarding whether our largest client would depart following a relocation to Manchester; matters because their departure would cost approximately £5M per year.",
+      kind: "unknown",
+      status: "unknown",
+      confidence: "medium",
+    });
+
+    const graph = makeGraphFor(unknown, {
+      centralStatement:
+        "We need to decide whether relocating is commercially justified.",
+    });
+
+    const result = formulateQuestion({ node: unknown, graph });
+
+    expect(result.question.toLowerCase()).toContain(
+      "whether our largest client would depart following a relocation to manchester",
+    );
+  });
+
+  it("direct interrogative label remains direct", () => {
+    const unknown = makeNode({
+      id: "unc-direct",
+      label: "Will our largest client leave if we relocate?",
+      description:
+        "Uncertainty regarding whether our largest client would depart following a relocation to Manchester; matters because their departure would cost approximately £5M per year.",
+      kind: "unknown",
+      status: "unknown",
+      confidence: "medium",
+    });
+
+    const graph = makeGraphFor(unknown, {
+      centralStatement:
+        "We need to decide whether relocating is commercially justified.",
+    });
+
+    const result = formulateQuestion({ node: unknown, graph });
+
+    expect(result.question).toBe("Will our largest client leave if we relocate?");
+  });
+
+  it("nominal label without explicit 'whether...' falls back to label-based extraction", () => {
+    const unknown = makeNode({
+      id: "unc-nominal",
+      label: "Service reliability uncertainty",
+      description: "Unknown service reliability.",
+      kind: "unknown",
+      status: "unknown",
+      confidence: "medium",
+    });
+
+    const result = formulateQuestion({
+      node: unknown,
+      graph: makeGraphFor(unknown),
+    });
+
+    expect(result.question).not.toContain("How should uncertainty regarding");
+  });
+
+  it("source description is never mutated by question formulation", () => {
+    const description =
+      "Unknown whether one prospective enterprise customer will sign if we launch this year, so that the remaining £700k of the expected £1.2M annual revenue is realized.";
+    const unknown = makeNode({
+      id: "unc-preserve",
+      label: "Prospective enterprise customer signing likelihood",
+      description,
+      kind: "unknown",
+      status: "unknown",
+      confidence: "medium",
+    });
+
+    const graph = makeGraphFor(unknown, {
+      centralStatement:
+        "We need to decide which launch timing option provides superior net value.",
+    });
+
+    formulateQuestion({ node: unknown, graph });
+
+    expect(unknown.description).toBe(description);
+  });
 });