Who was the last Monarch not to assent to an Act Parliament had voted for?

The last monarch not to assent to an Act of Parliament was King Edward VIII in 1936. He refused to give his assent to the Government of India Bill, which aimed to increase self-governance in India. However, his reign was short-lived, and he abdicated the throne later that year to marry Wallis Simpson. Consequently, no British monarch has withheld royal assent since then.