diff --git a/chat-finish-sync.mjs b/chat-finish-sync.mjs
index 3afee3b..4d62c6f 100644
--- a/chat-finish-sync.mjs
+++ b/chat-finish-sync.mjs
@@ -30,8 +30,41 @@ export function mergeConversationSnapshot(current, incoming) {
   }
   const base = Array.isArray(current) ? current : [];
   const incomingIds = new Set(incoming.map((message) => message?.id).filter(Boolean));
-  const localOnly = base.filter((message) => message?.id && !incomingIds.has(message.id));
-  return localOnly.length ? [...incoming, ...localOnly] : incoming;
+  const localOnlyByNextAnchor = new Map();
+
+  // Keep the regression-guard behaviour of retaining local streamed messages,
+  // but put them back between the same server messages instead of appending the
+  // whole local tail. Finish/UpdateConversation snapshots can temporarily omit
+  // a middle message while Goose is still persisting it.
+  for (let index = 0; index < base.length; index += 1) {
+    const message = base[index];
+    if (!message?.id || incomingIds.has(message.id)) continue;
+
+    let nextAnchor = null;
+    for (let cursor = index + 1; cursor < base.length; cursor += 1) {
+      const candidateId = base[cursor]?.id;
+      if (candidateId && incomingIds.has(candidateId)) {
+        nextAnchor = candidateId;
+        break;
+      }
+    }
+
+    const bucket = localOnlyByNextAnchor.get(nextAnchor) ?? [];
+    bucket.push(message);
+    localOnlyByNextAnchor.set(nextAnchor, bucket);
+  }
+
+  if (localOnlyByNextAnchor.size === 0) return incoming;
+
+  const merged = [];
+  for (const message of incoming) {
+    const before = localOnlyByNextAnchor.get(message?.id);
+    if (before?.length) merged.push(...before);
+    merged.push(message);
+  }
+  const trailing = localOnlyByNextAnchor.get(null);
+  if (trailing?.length) merged.push(...trailing);
+  return merged;
 }
 
 /**
diff --git a/chat-finish-sync.test.mjs b/chat-finish-sync.test.mjs
index 4f65be0..4910a8e 100644
--- a/chat-finish-sync.test.mjs
+++ b/chat-finish-sync.test.mjs
@@ -52,3 +52,31 @@ test('mergeSessionMessagesAfterFinish matches Finish sync merge semantics', () =
     ['u1', 'a1'],
   );
 });
+
+test('mergeConversationSnapshot keeps an omitted middle message between its anchors', () => {
+  const local = [
+    msg('u1', 'user', '第一轮'),
+    msg('a1', 'assistant', '第一轮回复'),
+    msg('u2', 'user', '第二轮'),
+    msg('a2', 'assistant', '第二轮回复'),
+  ];
+  const server = [local[0], local[1], local[3]];
+  assert.deepEqual(
+    mergeConversationSnapshot(local, server).map((message) => message.id),
+    ['u1', 'a1', 'u2', 'a2'],
+  );
+});
+
+test('mergeConversationSnapshot keeps local messages before the first and after the last server anchor', () => {
+  const local = [
+    msg('u0', 'user', '本地前置'),
+    msg('u1', 'user', '服务端消息'),
+    msg('a1', 'assistant', '服务端回复'),
+    msg('a2', 'assistant', '本地尾部'),
+  ];
+  const server = [local[1], local[2]];
+  assert.deepEqual(
+    mergeConversationSnapshot(local, server).map((message) => message.id),
+    ['u0', 'u1', 'a1', 'a2'],
+  );
+});
diff --git a/mindspace-public-delivery.mjs b/mindspace-public-delivery.mjs
index ea53b71..52d6f5f 100644
--- a/mindspace-public-delivery.mjs
+++ b/mindspace-public-delivery.mjs
@@ -5,6 +5,7 @@ import { injectMindSpacePageDataContext } from './mindspace-public-page-context.
 import { preparePublishedPlatformBrand } from './mindspace-page-tag.mjs';
 import { injectPublicImageRetryScript } from './mindspace-public-image-retry.mjs';
 import { applyWechatSurveyCompat } from './mindspace-page-data-wechat-survey-compat.mjs';
+import { stripPublicationHtmlCspMeta } from './plaza-embed.mjs';
 
 const INLINE_SCRIPT_PATTERN = /<script\b(?![^>]*\bsrc\b)[^>]*>([\s\S]*?)<\/script>/gi;
 
@@ -64,7 +65,12 @@ export function decorateMindSpacePublishedHtml({
   publishedPageCsp,
   isWechatUserAgent,
 } = {}) {
-  let nextHtml = html;
+  // Preview HTML carries a restrictive inline CSP (often script-src 'none').
+  // Published delivery sets the authoritative CSP response header below; keep
+  // the preview meta out of the delivered document so Page Data and other
+  // same-origin scripts are governed by that header instead of being blocked
+  // by a stale preview policy.
+  let nextHtml = stripPublicationHtmlCspMeta(html);
   let allowEmbedFrame = false;
 
   if (embed) {
diff --git a/mindspace-public-delivery.test.mjs b/mindspace-public-delivery.test.mjs
index 873c9cb..aeb61e4 100644
--- a/mindspace-public-delivery.test.mjs
+++ b/mindspace-public-delivery.test.mjs
@@ -137,6 +137,22 @@ test('decorateMindSpacePublishedHtml returns decorated html and csp', () => {
   assert.equal(options.scriptHashes.length, 4);
 });
 
+test('decorateMindSpacePublishedHtml removes preview CSP before published delivery', () => {
+  const result = decorateMindSpacePublishedHtml({
+    html: '<html><head><meta http-equiv="Content-Security-Policy" content="script-src \'none\'"></head><body><script>window.ready=1</script></body></html>',
+    context: { origin: '', pageUrl: '', pageDirUrl: '', fallbackImageUrl: '' },
+    preparePublicationHtmlForEmbed: (value) => value,
+    injectOgTags: (value) => value,
+    injectWechatShareBridge: (value) => value,
+    injectPublicFileShareButton: (value) => ({ html: value, scriptHashes: [] }),
+    publishedPageCsp: (value) => value,
+    isWechatUserAgent: () => false,
+  });
+
+  assert.doesNotMatch(result.html, /Content-Security-Policy/i);
+  assert.match(result.html, /window\.ready=1/);
+});
+
 test('decorateMindSpacePublishedHtml forwards isOwner=false to the share button injector', () => {
   let sharedIsOwner;
   decorateMindSpacePublishedHtml({
diff --git a/src/utils/message.ts b/src/utils/message.ts
index 93a7f42..14f0b9d 100644
--- a/src/utils/message.ts
+++ b/src/utils/message.ts
@@ -234,14 +234,20 @@ export function shouldShowChatMessage(message: Message): boolean {
 }
 
 export function pushMessage(messages: Message[], incoming: Message): Message[] {
-  const last = messages[messages.length - 1];
-  if (last?.id && incoming.id && last.id === incoming.id) {
+  const existingIndex = incoming.id
+    ? messages.findIndex((message) => message?.id === incoming.id)
+    : -1;
+  if (existingIndex >= 0) {
+    const existing = messages[existingIndex];
     return [
-      ...messages.slice(0, -1),
+      ...messages.slice(0, existingIndex),
       {
-        ...last,
-        content: mergeMessageContent(last.content, incoming.content) as MessageContent[],
+        ...existing,
+        ...incoming,
+        metadata: { ...existing.metadata, ...incoming.metadata },
+        content: mergeMessageContent(existing.content, incoming.content) as MessageContent[],
       },
+      ...messages.slice(existingIndex + 1),
     ];
   }
   return [...messages, incoming];