It is a built in scrollbar feature, unfortunately there is no option for that, but it's possible to turn it off by using a custom code.
I've made a small script snippet, which executes whenever the results are displayed, and reloads the scrollbar without the snapping function. Place this to the functions.php file in your active theme/child theme directory (copy from line 3):
!! Before any modifications, please have a back-up of your entire site including files, database etc.., in case anything goes wrong !!Best,
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