I have an AMD Radeon HD 7570, and the shadows have always rendered poorly in the game. Since the latest update, however, they actively appear to have gotten worse. Shadows appear to be made up of bizarre triangular "chunks". It looks quite ugly, and it's actually making it difficult to focus on the game.

Any chance of this being fixed in an upcoming patch?

Maybe the newest patch automatically set them to low quality. In the graphics options you will find you can set it to high quality again, or turn shadows off completely.