When using the keyboard to scroll items into view the highlighted item will change unexpectedly. It seems as though the item where the cursor is resting is re-highlighted when the offset of the list is changed (to bring the offscreen item you want to highlight into view).
I was able to reproduce this in Chrome, Firefox, and Safari, all on macOS Sierra (didn't try any other browsers).
When using the keyboard to scroll items into view the highlighted item will change unexpectedly. It seems as though the item where the cursor is resting is re-highlighted when the offset of the list is changed (to bring the offscreen item you want to highlight into view).
I was able to reproduce this in Chrome, Firefox, and Safari, all on macOS Sierra (didn't try any other browsers).