diff --git a/apps/web/components/markdown/Markdown.tsx b/apps/web/components/markdown/Markdown.tsx
index 00038dad..d09f31a5 100644
--- a/apps/web/components/markdown/Markdown.tsx
+++ b/apps/web/components/markdown/Markdown.tsx
@@ -3,7 +3,6 @@ import ReactMarkdown, { type Components } from 'react-markdown'
 import rehypeRaw from 'rehype-raw'
 import remarkGfm from 'remark-gfm'
 import { cn } from '@/lib/utils'
-import { MentionHoverCard } from '@/components/common/mention-hover-card'
 import { CodeBlock, InlineCode } from './CodeBlock'
 import { preprocessLinks } from './linkify'
 
@@ -61,15 +60,10 @@ function createComponents(
     a: ({ href, children }) => {
       // Mention links: mention://member/id or mention://agent/id
       if (href?.startsWith('mention://')) {
-        const parts = href.replace('mention://', '').split('/')
-        const mentionType = parts[0] ?? 'member'
-        const mentionId = parts[1] ?? ''
         return (
-          <MentionHoverCard type={mentionType} id={mentionId}>
-            <span className="text-primary font-semibold mx-0.5">
-              {children}
-            </span>
-          </MentionHoverCard>
+          <span className="text-primary font-semibold mx-0.5">
+            {children}
+          </span>
         )
       }
 
diff --git a/apps/web/features/issues/components/comment-input.tsx b/apps/web/features/issues/components/comment-input.tsx
index 6e2b8052..6aaa2041 100644
--- a/apps/web/features/issues/components/comment-input.tsx
+++ b/apps/web/features/issues/components/comment-input.tsx
@@ -1,7 +1,7 @@
 "use client";
 
 import { useRef, useState } from "react";
-import { ArrowUp } from "lucide-react";
+import { ArrowUp, Loader2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { RichTextEditor, type RichTextEditorRef } from "@/components/common/rich-text-editor";
 
@@ -44,7 +44,7 @@ function CommentInput({ onSubmit }: CommentInputProps) {
           disabled={isEmpty || submitting}
           onClick={handleSubmit}
         >
-          <ArrowUp className="h-4 w-4" />
+          {submitting ? <Loader2 className="h-4 w-4 animate-spin" /> : <ArrowUp className="h-4 w-4" />}
         </Button>
       </div>
     </div>
diff --git a/apps/web/features/issues/components/reply-input.tsx b/apps/web/features/issues/components/reply-input.tsx
index b95662c4..d58c8443 100644
--- a/apps/web/features/issues/components/reply-input.tsx
+++ b/apps/web/features/issues/components/reply-input.tsx
@@ -1,7 +1,7 @@
 "use client";
 
 import { useRef, useState } from "react";
-import { ArrowUp } from "lucide-react";
+import { ArrowUp, Loader2 } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { RichTextEditor, type RichTextEditorRef } from "@/components/common/rich-text-editor";
 import { ActorAvatar } from "@/components/common/actor-avatar";
@@ -83,7 +83,7 @@ function ReplyInput({
                 onClick={handleSubmit}
                 tabIndex={isEmpty ? -1 : 0}
               >
-                <ArrowUp className="h-3.5 w-3.5" />
+                {submitting ? <Loader2 className="h-3.5 w-3.5 animate-spin" /> : <ArrowUp className="h-3.5 w-3.5" />}
               </Button>
             </div>
           </div>
diff --git a/apps/web/features/issues/hooks/use-issue-timeline.ts b/apps/web/features/issues/hooks/use-issue-timeline.ts
index 98530d9a..63555d0c 100644
--- a/apps/web/features/issues/hooks/use-issue-timeline.ts
+++ b/apps/web/features/issues/hooks/use-issue-timeline.ts
@@ -176,27 +176,14 @@ export function useIssueTimeline(issueId: string, userId?: string) {
   const submitComment = useCallback(
     async (content: string) => {
       if (!content.trim() || submitting || !userId) return;
-      const tempId = "temp-" + Date.now();
-      const tempEntry: TimelineEntry = {
-        type: "comment",
-        id: tempId,
-        actor_type: "member",
-        actor_id: userId,
-        content,
-        parent_id: null,
-        created_at: new Date().toISOString(),
-        updated_at: new Date().toISOString(),
-        comment_type: "comment",
-      };
-      setTimeline((prev) => [...prev, tempEntry]);
       setSubmitting(true);
       try {
         const comment = await api.createComment(issueId, content);
-        setTimeline((prev) =>
-          prev.map((e) => (e.id === tempId ? commentToTimelineEntry(comment) : e)),
-        );
+        setTimeline((prev) => {
+          if (prev.some((e) => e.id === comment.id)) return prev;
+          return [...prev, commentToTimelineEntry(comment)];
+        });
       } catch {
-        setTimeline((prev) => prev.filter((e) => e.id !== tempId));
         toast.error("Failed to send comment");
       } finally {
         setSubmitting(false);
@@ -208,26 +195,13 @@ export function useIssueTimeline(issueId: string, userId?: string) {
   const submitReply = useCallback(
     async (parentId: string, content: string) => {
       if (!content.trim() || !userId) return;
-      const tempId = "temp-" + Date.now();
-      const tempEntry: TimelineEntry = {
-        type: "comment",
-        id: tempId,
-        actor_type: "member",
-        actor_id: userId,
-        content,
-        parent_id: parentId,
-        created_at: new Date().toISOString(),
-        updated_at: new Date().toISOString(),
-        comment_type: "comment",
-      };
-      setTimeline((prev) => [...prev, tempEntry]);
       try {
         const comment = await api.createComment(issueId, content, "comment", parentId);
-        setTimeline((prev) =>
-          prev.map((e) => (e.id === tempId ? commentToTimelineEntry(comment) : e)),
-        );
+        setTimeline((prev) => {
+          if (prev.some((e) => e.id === comment.id)) return prev;
+          return [...prev, commentToTimelineEntry(comment)];
+        });
       } catch {
-        setTimeline((prev) => prev.filter((e) => e.id !== tempId));
         toast.error("Failed to send reply");
       }
     },