If defaultHighlightedIndex prop is passed to Downshift, opening the list with Up/Down Arrow will highlight the defaultHighlightedIndex -/+ 1.
At the moment the behaviour is to highlight 0/count - 1 when you open the list with Down/Up Arrow. This behaviour will not be changed if you don't pass defaultHighlightedIndex. It will act as a default.
Work in progress, will add a PR today, maybe tomorrow.
downshift version: 3.1.12
node version: 10.13.0
npm (or yarn) version: 6.4.1