I faced the same problem and try to solve, but unfortunately it wouldn't work anymore ! If you are facing the same problem and can't find the solution, it may help you.
If you configure jquery/jquery-ui globally in webpack, you need to import autocomplete like this
import { autocomplete } from 'webpack-jquery-ui';
And you must include jquery-ui.css in the head section of html, i don't understand why its not working without it!
<link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css">
Hope your problem will be solved.
And make sure you include/install the following three