When opening a <SelectField> that contains enough elements to scroll and having one item pre-selected (value property set) causes the appear-animation to show the wrong scroll position. Once the animation completes the menu jumps to the final position:

This varies in base of number of elements contained and which element selected. It is also very noticeable on mobile (Samsung S7) and can be reproduced constantly.

Try yourself on WebpackBin. If you can't reproduce, maybe try different number of items / different preselection.

The above was recorded on Desktop with Chrome 55 on a 4K display (60Hz, if that matters) on Windows.

When I move the browser window to a secondary 1050p monitor and do the test there, then it looks better:

So this might be related to high density displays .