diff --git a/web/zebra-spaces.html b/web/zebra-spaces.html
index 84ef5c1..a3fb8b2 100644
--- a/web/zebra-spaces.html
+++ b/web/zebra-spaces.html
@@ -1254,6 +1254,9 @@ async function sfuSubscribe(){
      * delay which is well below noticeable. */
     try { ev.receiver.playoutDelayHint = 0.4; } catch(_){}
     const pubHex = sid;
+    /* never play our own mic back to ourselves — the SFU echoes our
+     * publish to every sub including our own (we always subscribe now) */
+    if (myKeys && pubHex === myKeys.pubHex) return;
     /* cache stream by publisher pubkey so it survives the member's session
      * uuid changing across leave/rejoin — see flushSfuStreams */
     sfuStreamsByPubHex.set(pubHex, ev.streams[0]);
@@ -1296,21 +1299,35 @@ async function sfuSubscribe(){
   if (!ackRes.ok){ pc.close(); throw new Error('sfu subscribe-answer http '+ackRes.status); }
   sfuSubPC = pc; sfuSubPeerID = offer.peer_id;
   /* SSE: server pushes renegotiation offers when publisher set changes.
-   * We answer each via POST /answer. ping events are keepalive only. */
+   * We answer each via POST /answer. ping events are keepalive only.
+   *
+   * Renegotiation must be SERIALISED. Each offer transitions the PC
+   * through have-remote-offer → stable, and if we kick off the next
+   * setRemoteDescription before the previous has applied its answer,
+   * the second one throws ('failed to set remote offer sdp: Called in
+   * wrong state'). When a speaker publishes mic + screen + camera in
+   * quick succession the SFU fires three offers in a row — without
+   * serialisation we drop the later ones, browser-side track set goes
+   * out of sync with the SFU, and existing screen/camera tiles can
+   * stop receiving RTP. Chain through a single promise queue. */
+  let renegQueue = Promise.resolve();
   sfuSubEvents = new EventSource(SFU_BASE + '/events?room=' + encodeURIComponent(roomID) + '&peer=' + sfuSubPeerID);
-  sfuSubEvents.onmessage = async (ev) => {
+  sfuSubEvents.onmessage = (ev) => {
     let m; try { m = JSON.parse(ev.data); } catch(_){ return; }
     if (m.type !== 'offer' || !sfuSubPC) return;
-    try {
-      await sfuSubPC.setRemoteDescription({ type:'offer', sdp: m.sdp });
-      const ans = await sfuSubPC.createAnswer();
-      await sfuSubPC.setLocalDescription(ans);
-      await waitForIceGathering(sfuSubPC);
-      await fetch(SFU_BASE + '/answer?room=' + encodeURIComponent(roomID) + '&peer=' + sfuSubPeerID, {
-        method:'POST', headers:{'Content-Type':'application/json'},
-        body: JSON.stringify({ sdp: sfuSubPC.localDescription.sdp })
-      });
-    } catch(e){ logLine('err','sfu renegotiate: '+e.message); }
+    renegQueue = renegQueue.then(async () => {
+      if (!sfuSubPC) return;
+      try {
+        await sfuSubPC.setRemoteDescription({ type:'offer', sdp: m.sdp });
+        const ans = await sfuSubPC.createAnswer();
+        await sfuSubPC.setLocalDescription(ans);
+        await waitForIceGathering(sfuSubPC);
+        await fetch(SFU_BASE + '/answer?room=' + encodeURIComponent(roomID) + '&peer=' + sfuSubPeerID, {
+          method:'POST', headers:{'Content-Type':'application/json'},
+          body: JSON.stringify({ sdp: sfuSubPC.localDescription.sdp })
+        });
+      } catch(e){ logLine('err','sfu renegotiate: '+e.message); }
+    });
   };
   sfuSubEvents.onerror = () => { /* EventSource auto-reconnects */ };
   logLine('', 'sfu: subscribed as '+shortHex(sfuSubPeerID));
@@ -2415,8 +2432,8 @@ logLine('', 'ready — pick a handle, type a rendezvous code, enter the space');
 
 <footer style="margin:2.2rem auto 0;font-size:0.65rem;color:#999;line-height:1.7;word-break:break-all;font-family:monospace">
   <span id="pi-seal" style="color:#777;cursor:default;user-select:none" title="">page integrity</span> &nbsp;·&nbsp; built <span class="stamp-date">2026-06-02</span><br>
-  md5 <span class="stamp-md5">e1c393db6371901f9dd2bc5f30195cf1</span><br>
-  sha256 <span class="stamp-sha">b7c89d66d504eb2765bac6c128f31d07df03bc7f4309e4f6173811212510bb71</span><br>
+  md5 <span class="stamp-md5">4d956692f61f60657077d2e04b576b71</span><br>
+  sha256 <span class="stamp-sha">eb02187ba33a4618b347444a41e25d6d2f58ff6c52c7f7ff0e3437a020dbfa25</span><br>
   <span style="color:#bbb">hashes are of this page with these two fields zeroed — to verify, blank them and re-hash</span><br>
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