With the newest release of Lightroom classic, when I am in grid view and want to highlight a new image I would normally move or hover the mouse to the image I want to highlight. The border lightens and signals I can click to select that image. With this release, move the mouse does not always highlight an image, so it can not be selected with the mouse. I noticed an image with a thin border will not highlight at all with the mouse. The adjacent image border will highlight if the cursor is in certain positions, the image next to that will highlight the border no matter the cursor position. Using the arrow keys works and selects the next image.