Horizon Forbidden West has been updated to version 1.09 today by Guerrilla Games. You can get the complete patch notes from here.
There are a number of fixes made in this new patch but most of it has to do with quest or progression bugs. The developers still haven’t resolved the issues with the visual shimmering which has been reported since the launch of the game. You can learn more about this update in the patch notes given below, or take a look at the reddit thread.