diff --git a/src/lib/components/common/RichTextInput.svelte b/src/lib/components/common/RichTextInput.svelte
index e4c469acd5..53a042b6f5 100644
--- a/src/lib/components/common/RichTextInput.svelte
+++ b/src/lib/components/common/RichTextInput.svelte
@@ -94,6 +94,12 @@
 		}
 	});
 
+	// Registered after use(gfm) to override its checkbox rule; taskListItems owns the marker.
+	turndownService.addRule('taskItemCheckbox', {
+		filter: (node) => node.nodeName === 'INPUT' && node.getAttribute('type') === 'checkbox',
+		replacement: () => ''
+	});
+
 	turndownService.addRule('taskListItems', {
 		filter: (node) =>
 			node.nodeName === 'LI' &&
@@ -101,7 +107,8 @@
 				node.getAttribute('data-checked') === 'false'),
 		replacement: function (content, node) {
 			const checked = node.getAttribute('data-checked') === 'true';
-			content = content.replace(/^\s+/, '');
+			// Trim TipTap's block wrapper; 4-space continuation keeps sublists and fences nested.
+			content = content.trim().replace(/\n(?=.)/g, '\n    ');
 			return `- [${checked ? 'x' : ' '}] ${content}\n`;
 		}
 	});