diff --git a/frontend/user/modules/detail-drawer.js b/frontend/user/modules/detail-drawer.js
index 18969a6..8adb900 100644
--- a/frontend/user/modules/detail-drawer.js
+++ b/frontend/user/modules/detail-drawer.js
@@ -159,9 +159,9 @@ export function initDrawer({ root, store }) {
     }
     const kpis = pickKpisFor(mode, detail);
     const bars = bucketBars({
-      low: detail.low ?? 0,
-      mid: detail.mid ?? 0,
-      high: detail.high ?? 0,
+      low: detail.low,
+      mid: detail.mid,
+      high: detail.high,
     });
     return [
       renderKpiRow(kpis),
diff --git a/frontend/user/modules/drawer-data.js b/frontend/user/modules/drawer-data.js
index 96800a4..86c89ae 100644
--- a/frontend/user/modules/drawer-data.js
+++ b/frontend/user/modules/drawer-data.js
@@ -93,19 +93,26 @@ export function qualityLabelFor(status) {
   }[status] || "待复核";
 }
 
-export function bucketBars({ low = 0, mid = 0, high = 0 } = {}) {
+export function bucketBars({ low, mid, high } = {}) {
   const values = [
-    { key: "low", label: "低层", value: Number(low) || 0 },
-    { key: "mid", label: "中层", value: Number(mid) || 0 },
-    { key: "high", label: "高层", value: Number(high) || 0 },
+    { key: "low", label: "低层", value: coerceFiniteOrNull(low) },
+    { key: "mid", label: "中层", value: coerceFiniteOrNull(mid) },
+    { key: "high", label: "高层", value: coerceFiniteOrNull(high) },
   ];
-  const max = Math.max(...values.map((v) => v.value));
+  const finiteValues = values.map((v) => v.value).filter((v) => v !== null);
+  const max = finiteValues.length ? Math.max(...finiteValues) : 0;
   return values.map((v) => ({
     ...v,
-    pct: max > 0 ? Math.round((v.value / max) * 100) : 0,
+    pct: v.value !== null && max > 0 ? Math.round((v.value / max) * 100) : 0,
   }));
 }
 
+function coerceFiniteOrNull(raw) {
+  if (raw === null || raw === undefined) return null;
+  const n = Number(raw);
+  return Number.isFinite(n) ? n : null;
+}
+
 export function pickKpisFor(modeId, detail) {
   const kpis = KPI_MAP[modeId] || KPI_MAP.yield;
   return kpis(detail);
diff --git a/tests/frontend/test_drawer_data.mjs b/tests/frontend/test_drawer_data.mjs
index 4879b98..05dc259 100644
--- a/tests/frontend/test_drawer_data.mjs
+++ b/tests/frontend/test_drawer_data.mjs
@@ -132,6 +132,44 @@ test("bucketBars: handles all-zero/empty without dividing by zero", () => {
   assert.equal(bars[2].pct, 0);
 });
 
+test("bucketBars: null / non-finite floor inputs drop to null (real 0 is preserved)", () => {
+  // Floor bucket values come from the pipeline. Missing buckets land as null,
+  // and a divide-by-zero leak or corrupt payload can produce ±Infinity / NaN.
+  // None of these are real measurements: bucketBars must surface them as null
+  // so formatBucketValue renders "—" — never a fake "0" (which would imply a
+  // real zero-yield bucket and put a zero-height bar next to real buckets) and
+  // never the literal string "Infinity" (which leaks through `Number(v) || 0`
+  // because Infinity is truthy). A real numeric 0 stays 0.
+  const bars = bucketBars({
+    low: null,
+    mid: Number.POSITIVE_INFINITY,
+    high: 0,
+  });
+  assert.equal(bars[0].value, null);
+  assert.equal(bars[1].value, null);
+  assert.equal(bars[2].value, 0);
+  // Missing buckets contribute 0 to the bar-height scale and don't anchor max.
+  assert.equal(bars[0].pct, 0);
+  assert.equal(bars[1].pct, 0);
+  assert.equal(bars[2].pct, 0);
+});
+
+test("bucketBars: NaN / -Infinity drop to null while finite siblings still scale", () => {
+  // Sibling test: when one bucket is non-finite but others are real, the real
+  // ones must still scale against each other (max is taken over finite values).
+  const bars = bucketBars({
+    low: Number.NaN,
+    mid: 2,
+    high: 4,
+  });
+  assert.equal(bars[0].value, null);
+  assert.equal(bars[1].value, 2);
+  assert.equal(bars[2].value, 4);
+  assert.equal(bars[0].pct, 0);
+  assert.equal(bars[1].pct, 50);
+  assert.equal(bars[2].pct, 100);
+});
+
 test("pickKpisFor: yield mode focuses on yield/payback/score/sample", () => {
   const detail = {
     yieldAvg: 0.04,