I have the same issue.
A temporary fix is to add this CSS:
ul.react-datepicker__time-list {
padding: 0;
}
Trying to pin this down a bit more, but I only had this issue when I moved from using materialize CSS to bootstrap 4. Perhaps materialize was masking this issue by setting padding 0 on ul.
after made the ul padding to 0. some browser works, but in a screen it is showing

It seems to be the ul.react-datepicker__time-list element, which inherits from the base 'user agent stylesheet' (in chrome at least) with this class:
ul, menu, dir {
padding-inline-start:40px;
}
Guess we need to reset this to 0px, as mentioned above...
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Most helpful comment
A temporary fix is to add this CSS: