diff --git a/docs/web-network-captures.md b/docs/web-network-captures.md
index 5a5f75ef42..4cd975ff99 100644
--- a/docs/web-network-captures.md
+++ b/docs/web-network-captures.md
@@ -820,7 +820,7 @@ by null; there is no single events pointer shared by all traces.
 | Original event and loss declaration | Observed endpoint report; `recovery:packet_lost` does not prove actual network loss. Missing packet number/type remains unknown.                                                                                                                                              |
 | STREAM ranges and byte totals       | Derived per trace and direction from reported offsets and lengths using exact integer arithmetic. `unique_bytes` unions intervals; `frame_length_sum` includes overlaps; `repeated_bytes` is their difference. Overlap alone does not prove retransmission or equal contents. |
 | FIN final sizes                     | Reported offset plus length where FIN is true; multiple conflicting sizes remain visible. A final size does not establish complete coverage or a received body.                                                                                                               |
-| Incomplete fact records             | Ordinals with omitted/redacted interpretable frame metadata; usable fields in other records survive. An empty list does not establish complete logging or capture.                                                                                                            |
+| Incomplete fact records             | Ordinals with omitted/redacted interpretable frame metadata, including an unknown STREAM FIN; usable fields such as known ranges in that record survive. An empty list does not establish complete logging or capture.                                                        |
 | HTTP bodies and causality           | `body_bytes: "not-reported"`; lengths and headers are metadata, with no reconstructed body, hash, timing causality or live process attribution.                                                                                                                               |
 
 QUIC integer fields interpreted here accept exact nonnegative JSON integer
diff --git a/src/browser/history/QlogCapture.test.ts b/src/browser/history/QlogCapture.test.ts
index 2b2942b2e6..3b99c2e758 100644
--- a/src/browser/history/QlogCapture.test.ts
+++ b/src/browser/history/QlogCapture.test.ts
@@ -134,6 +134,38 @@ it("keeps incomplete fields unknown and FIN without bytes as metadata", () => {
   expect(traces[0]?.loss_declarations[0]?.packet_number.state).toBe("unknown");
 });
 
+it.each([
+  { fin: undefined, incomplete: [0] },
+  { fin: null, incomplete: [0] },
+  { fin: false, incomplete: [] },
+  { fin: true, incomplete: [] },
+])(
+  "retains STREAM ranges and marks unknown FIN records incomplete: $fin",
+  ({ fin, incomplete }) => {
+    const streamFrame: Record<string, unknown> = {
+      frame_type: "stream",
+      stream_id: 4,
+      offset: 8,
+      length: 3,
+    };
+    if (fin !== undefined) streamFrame.fin = fin;
+    const { traces } = facts(capture([event([streamFrame])]));
+    expect(traces[0]?.incomplete_fact_records).toEqual(incomplete);
+    expect(traces[0]?.streams[0]?.contributions).toEqual([
+      {
+        record_ordinal: 0,
+        frame_index: 0,
+        offset: "8",
+        length: "3",
+        fin: typeof fin === "boolean" ? fin : null,
+      },
+    ]);
+    expect(traces[0]?.streams[0]?.covered_ranges).toEqual([
+      { start: "8", end: "11" },
+    ]);
+  },
+);
+
 it("excludes structural auth material and explicit normalized values without guessing extension secrecy", () => {
   const text = capture([
     {
diff --git a/src/browser/history/QlogCapture.ts b/src/browser/history/QlogCapture.ts
index 245ec1fd85..f740fbd52f 100644
--- a/src/browser/history/QlogCapture.ts
+++ b/src/browser/history/QlogCapture.ts
@@ -312,6 +312,8 @@ const collectTransportFacts = (
       length: length.toString(),
       fin: typeof frame.fin === "boolean" ? frame.fin : null,
     });
+    if (typeof frame.fin !== "boolean")
+      fact.incomplete_fact_records.push(ordinal);
   }
 };
 
diff --git a/tests/acceptance/tools/qlogCapture.test.ts b/tests/acceptance/tools/qlogCapture.test.ts
index eafaf0ad4f..3691c685dc 100644
--- a/tests/acceptance/tools/qlogCapture.test.ts
+++ b/tests/acceptance/tools/qlogCapture.test.ts
@@ -29,9 +29,7 @@ const event = {
   time: 1791819895000.25,
   data: {
     header: { packet_type: "1RTT", packet_number: 5 },
-    frames: [
-      { frame_type: "stream", stream_id: 0, offset: 10, length: 5, fin: true },
-    ],
+    frames: [{ frame_type: "stream", stream_id: 0, offset: 10, length: 5 }],
   },
 };
 const qlog = (events: unknown[]) =>
@@ -60,7 +58,7 @@ const assertAdditionalQlogFacets = async (
       { kind: "qlog", facet: "loss-declarations", trace_index: 0 },
       [{ record_ordinal: 1, packet_number: { state: "reported", value: "5" } }],
     ],
-    [{ kind: "qlog", facet: "incomplete-records", trace_index: 0 }, []],
+    [{ kind: "qlog", facet: "incomplete-records", trace_index: 0 }, [0]],
     [
       {
         kind: "qlog",
@@ -79,7 +77,7 @@ const assertAdditionalQlogFacets = async (
         stream_id: "0",
         direction: "sent",
       },
-      ["15"],
+      [],
     ],
     [{ kind: "qlog", facet: "traces", offset: 99 }, []],
   ] as const) {
@@ -206,7 +204,15 @@ it("pages original trace-scoped facts after source deletion without conflating s
   );
   expect(contribution.normalized_result).toMatchObject({
     page: {
-      items: [{ record_ordinal: 0, frame_index: 0, offset: "10", length: "5" }],
+      items: [
+        {
+          record_ordinal: 0,
+          frame_index: 0,
+          offset: "10",
+          length: "5",
+          fin: null,
+        },
+      ],
     },
     coverage: { total: 1, exhausted: true },
   });