Url path repeating and /views/ajax appearing in url

Problem/Motivation

This is being caused by using Url::fromRoute method.

Steps to reproduce

Hit the pager, and you will see the current path repeated, then it will be replaced with /views/ajax when further sets are returned.

Proposed resolution

I think it would be better to use the Url::fromUserInput method and have the first argument passed to the method be '?'
This will ensure a clean "page" param / prevent the path from being included in params.