diff --git a/packages/nc-gui/components/cell/RichText.vue b/packages/nc-gui/components/cell/RichText.vue
index c4e85fcdb8..93eafbc503 100644
--- a/packages/nc-gui/components/cell/RichText.vue
+++ b/packages/nc-gui/components/cell/RichText.vue
@@ -125,7 +125,7 @@ const getTiptapExtensions = () => {
       emptyEditorClass: 'is-editor-empty',
       placeholder: props.placeholder,
     }),
-    Markdown.configure({ breaks: true, transformPastedText: true, transformCopiedText: true }),
+    Markdown.configure({ breaks: true, transformPastedText: true }),
   ]
 
   if (appInfo.value.ee && !props.hideMention) {
diff --git a/packages/nc-gui/components/smartsheet/expanded-form/RichComment.vue b/packages/nc-gui/components/smartsheet/expanded-form/RichComment.vue
index 3705127faf..d74b2e81e8 100644
--- a/packages/nc-gui/components/smartsheet/expanded-form/RichComment.vue
+++ b/packages/nc-gui/components/smartsheet/expanded-form/RichComment.vue
@@ -62,7 +62,7 @@ const tiptapExtensions = [
     emptyEditorClass: 'is-editor-empty',
     placeholder: props.placeholder,
   }),
-  Markdown.configure({ breaks: true, transformPastedText: true, transformCopiedText: true }),
+  Markdown.configure({ breaks: true, transformPastedText: true }),
 ]
 
 const editor = useEditor({
diff --git a/packages/nc-gui/helpers/tiptap/extensions/functionality/markdown/markdown.ts b/packages/nc-gui/helpers/tiptap/extensions/functionality/markdown/markdown.ts
index 0646e5fa1a..d2dc945df8 100644
--- a/packages/nc-gui/helpers/tiptap/extensions/functionality/markdown/markdown.ts
+++ b/packages/nc-gui/helpers/tiptap/extensions/functionality/markdown/markdown.ts
@@ -25,6 +25,10 @@ export interface NcMarkdownParserConstructorType {
   maxBlockTokens?: number // Add this to limit block tokens
 }
 
+// Precompiled regex patterns
+const taskRegex = /^(?!.*- )(\s*)\[( |x|X)\]/gm // Matches unchecked and checked tasks
+const strikeThroughRegex = /(?<!~)~(?!~)(.*?)(?<!~)~(?!~)/g // Matches strikethrough syntax
+
 export class NcMarkdownParser {
   private static instance: NcMarkdownParser | null = null
   private md: MarkdownIt
@@ -90,17 +94,17 @@ export class NcMarkdownParser {
 
   public static preprocessMarkdown(markdownText: string, isEditor = false): string {
     if (!ncIsString(markdownText)) return markdownText ?? ''
-
+    // Only process task lists if not in editor mode
     if (!isEditor) {
       // Replace [ ] and [x] with GitHub-style checklist syntax only if not already prefixed with "- "
-      markdownText = markdownText.replace(/^(?!.*- )(\s*)\[ \]/gm, '$1- [ ]') // Replace unchecked tasks
-      markdownText = markdownText.replace(/^(?!.*- )(\s*)\[x\]/gm, '$1- [x]') // Replace checked tasks (lowercase 'x')
-      markdownText = markdownText.replace(/^(?!.*- )(\s*)\[X\]/gm, '$1- [x]') // Replace checked tasks (uppercase 'X')
+      markdownText = markdownText.replace(taskRegex, (_match, spaces, state) => {
+        const checked = state.toLowerCase() === 'x' ? '[x]' : '[ ]'
+        return `${spaces}- ${checked}`
+      })
     }
 
-    markdownText = markdownText.replace(/(?<!~)~(?!~)(.*?)(?<!~)~(?!~)/g, '<s>$1</s>')
-
-    return markdownText
+    // Replace single tilde strikethrough syntax with <s> tags
+    return markdownText.replace(strikeThroughRegex, '<s>$1</s>')
   }
 
   /**