Pasting into code block doubles the content

[cloverich]

• I enter ```
• I paste some code
• Its duplicated

Direct example of what I pasted (doubtful it matters):

  updateSearch = (document: EditableDocument) => {
    const idx = this.docs.findIndex((d) => d.id === document.id);
    if (idx === -1) return;

    const item = toSearchItem(document);
    if (!item) return;

    this.docs[idx] = item;
  };

Probably the normalizer when it see's multiple lines or something.