diff --git a/plugins/provider-codex/src/bridge/bridge.ts b/plugins/provider-codex/src/bridge/bridge.ts
index 043249502..82a216411 100644
--- a/plugins/provider-codex/src/bridge/bridge.ts
+++ b/plugins/provider-codex/src/bridge/bridge.ts
@@ -349,6 +349,13 @@ interface CodexBridgeSession {
   openedItemIds: Set<string>;
   /** Codex-id space; open turns settle as failed if the child dies. */
   openCodexTurnIds: Set<string>;
+  /**
+   * Codex-id space; every turn this session has emitted turn/started for.
+   * Thread-state snapshots for any other turn are replays (codex re-emits the
+   * rollout's last-turn usage on thread/resume and thread/fork) and must not
+   * be scoped to a bridge turn id bb has never seen (#1727).
+   */
+  startedCodexTurnIds: Set<string>;
   identityAnnounced: boolean;
   /**
    * Events translated before the session's identity is known (codex can emit
@@ -625,6 +632,23 @@ function toCanonicalEvents(
 
   if (event.type === "turn/started" && event.scope.kind === "turn") {
     session.openCodexTurnIds.add(event.scope.turnId);
+    session.startedCodexTurnIds.add(event.scope.turnId);
+  }
+  // Replayed thread-state snapshot (thread/resume, thread/fork): the turn it
+  // names was never started in this session, so its bridge-minted turn id
+  // would be unknown to bb. Context-window usage is session state and may be
+  // thread-scoped; token usage is turn-only and, on resume, duplicates the
+  // snapshot bb already persisted for that turn, so drop it.
+  if (
+    (event.type === "thread/tokenUsage/updated" ||
+      event.type === "thread/contextWindowUsage/updated") &&
+    event.scope.kind === "turn" &&
+    !session.startedCodexTurnIds.has(event.scope.turnId)
+  ) {
+    if (event.type === "thread/contextWindowUsage/updated") {
+      out.push(remapEvent(session, { ...event, scope: { kind: "thread" } }));
+    }
+    return out;
   }
   if (event.type === "turn/completed" && event.scope.kind === "turn") {
     session.openCodexTurnIds.delete(event.scope.turnId);
@@ -1066,6 +1090,7 @@ async function constructThreadSession(
     ),
     openedItemIds: new Set(),
     openCodexTurnIds: new Set(),
+    startedCodexTurnIds: new Set(),
     identityAnnounced: false,
     pendingPreIdentityEvents: [],
     openWorkReported: false,