After looking at the CSS, it looks like the position is fixed. I tested switching its position to absolute and it actually displays perfectly under the input, until you scroll anywhere and then It moves away.
@kwest I checked a few of our examples and I didn’t run into this issue, is it possible to re-create a minimal reproduction of the autocomplete setup you have? It may come down to something specific within your CSS.
Parent div with class .aa-Panel has position:absolute
Child div with classes .aa-PanelLayout .aa-Panel--scrollable has position: relative
I have a scrollable sandbox here if you want to take a look and see if you can find what you are missing: