Eurovision has strict rules: singers must sing without playback and without autotune. Some artists have complained that due to the fact that this is a double event, what you hear on the television broadcast is not what the live audience and the artist himself hear.
But if that's the problem, it's not clear why it happens only to some artists. We'll fix it! If you find a mistake in the article, please share it with us. We'd like to hear from you.