diff --git a/packages/core/src/extensions/keymap.ts b/packages/core/src/extensions/keymap.ts
index d16346fe506..ad584723068 100644
--- a/packages/core/src/extensions/keymap.ts
+++ b/packages/core/src/extensions/keymap.ts
@@ -18,7 +18,7 @@ export const Keymap = Extension.create({
         const { selection, doc } = tr
         const { empty, $anchor } = selection
         const { pos, parent } = $anchor
-        const $parentPos = $anchor.parent.isTextblock ? tr.doc.resolve(pos - 1) : $anchor
+        const $parentPos = $anchor.parent.isTextblock && pos > 0 ? tr.doc.resolve(pos - 1) : $anchor
         const parentIsIsolating = $parentPos.parent.type.spec.isolating
 
         const parentPos = $anchor.pos - $anchor.parentOffset