Consider a language model trained with a self-supervised objective where it learns to fill in randomly blanked-out words in a text. If the model encounters the sentence 'The artist picked up a [MASK] and a [MASK] to begin the painting,' it will try to predict the two missing words. However, it will predict each missing word without considering what the other missing word might be. Analyze the potential problem this creates for generating a coherent and logical sentence completion.