diff --git a/sdk/typescript/_bundled_plugin/scripts/workbench_scan_history.py b/sdk/typescript/_bundled_plugin/scripts/workbench_scan_history.py
index f2cb297e..323fdbe7 100644
--- a/sdk/typescript/_bundled_plugin/scripts/workbench_scan_history.py
+++ b/sdk/typescript/_bundled_plugin/scripts/workbench_scan_history.py
@@ -256,7 +256,7 @@ def list_unmatched_scan_pairs(
     }
     batches = []
     skipped = 0
-    backfilled: set[str] = set()
+    matching_findings: dict[str, list[dict[str, Any]]] = {}
     for index, after in enumerate(available):
         previous = [
             before
@@ -267,21 +267,19 @@ def list_unmatched_scan_pairs(
         if not previous:
             continue
         for scan in (*previous, after):
-            if scan["id"] not in backfilled:
+            if scan["id"] not in matching_findings:
                 backfill_finding_details(connection, scan)
-                backfilled.add(scan["id"])
+                matching_findings[scan["id"]] = [
+                    _matching_input(row)
+                    for row in _scan_findings(connection, scan["id"]).values()
+                ]
         batches.append(
             {
-                "afterFindings": [
-                    _matching_input(row) for row in _scan_findings(connection, after["id"]).values()
-                ],
+                "afterFindings": matching_findings[after["id"]],
                 "afterScanId": after["id"],
                 "beforeScans": [
                     {
-                        "findings": [
-                            _matching_input(row)
-                            for row in _scan_findings(connection, before["id"]).values()
-                        ],
+                        "findings": matching_findings[before["id"]],
                         "scanId": before["id"],
                     }
                     for before in previous
diff --git a/sdk/typescript/tests-ts/workbench-scan-history.test.ts b/sdk/typescript/tests-ts/workbench-scan-history.test.ts
new file mode 100644
index 00000000..65529e87
--- /dev/null
+++ b/sdk/typescript/tests-ts/workbench-scan-history.test.ts
@@ -0,0 +1,66 @@
+import { spawnSync } from "node:child_process";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { expect, test } from "bun:test";
+import { PLUGIN_ROOT } from "./plugin-root.js";
+
+test("loads each scan's matching findings once across historical batches", () => {
+  const python = Bun.which("python3") ?? Bun.which("python") ?? Bun.which("py");
+  expect(python).not.toBeNull();
+  if (python === null) throw new Error("A Python interpreter is required.");
+
+  const probe = [
+    "import argparse, json, sqlite3, sys",
+    "sys.path.insert(0, sys.argv[1])",
+    "import workbench_scan_history as history",
+    "connection = sqlite3.connect(':memory:')",
+    "connection.row_factory = sqlite3.Row",
+    "connection.executescript('''",
+    "CREATE TABLE security_targets (id TEXT, current_path TEXT);",
+    "CREATE TABLE scans (id TEXT, target_path TEXT, target_id TEXT, status TEXT, started_at TEXT);",
+    "CREATE TABLE scan_comparisons (before_scan_id TEXT, after_scan_id TEXT);",
+    "CREATE TABLE finding_occurrences (id TEXT, finding_id TEXT, scan_id TEXT, details_json TEXT, remediation TEXT, severity TEXT, summary TEXT, title TEXT);",
+    "CREATE TABLE finding_triage (occurrence_id TEXT, status TEXT, close_reason TEXT);",
+    "CREATE TABLE finding_locations (occurrence_id TEXT, relative_path TEXT, role TEXT, sort_order INTEGER);",
+    "''')",
+    "for index in range(3):",
+    "    scan = f'scan-{index}'",
+    "    connection.execute('INSERT INTO scans VALUES (?, ?, NULL, ?, ?)', (scan, sys.argv[2], 'complete', str(index)))",
+    "    connection.execute('INSERT INTO finding_occurrences VALUES (?, ?, ?, ?, ?, ?, ?, ?)', (scan, scan, scan, '{}', 'fix', 'high', 'summary', 'title'))",
+    "queries = []",
+    "connection.set_trace_callback(queries.append)",
+    "backfilled = []",
+    "result = history.list_unmatched_scan_pairs(connection, argparse.Namespace(repository=sys.argv[2], force=False), backfill_finding_details=lambda _connection, scan: backfilled.append(scan['id']), read_coverage=lambda _scan: {})",
+    "print(json.dumps({'result': result, 'backfilled': backfilled, 'findingQueries': sum('FROM finding_occurrences AS occurrences' in query for query in queries)}))",
+  ].join("\n");
+
+  const result = spawnSync(
+    python,
+    [
+      "-I",
+      "-B",
+      "-c",
+      probe,
+      join(PLUGIN_ROOT, "scripts"),
+      join(tmpdir(), "codex-security-matching-fixture"),
+    ],
+    { encoding: "utf8", timeout: 10_000 },
+  );
+
+  expect(result.status).toBe(0);
+  expect(result.stderr).toBe("");
+  expect(JSON.parse(result.stdout)).toMatchObject({
+    backfilled: ["scan-0", "scan-1", "scan-2"],
+    findingQueries: 3,
+    result: {
+      scanCount: 3,
+      batches: [
+        { afterScanId: "scan-1", beforeScans: [{ scanId: "scan-0" }] },
+        {
+          afterScanId: "scan-2",
+          beforeScans: [{ scanId: "scan-0" }, { scanId: "scan-1" }],
+        },
+      ],
+    },
+  });
+});