Great question — answering as the UphillTech team:
It's not a completely different URL, it's just your homepage URL with some query vars. A plugin probably uses this link somewhere on your website. That would be why this 'SEO scan' picks this up. It sounds like this is more of a problem within your SEO tool than it is a problem within your WordPress installation.
Full answer by DeltaG: https://wordpress.stackexchange.com/a/400613 (CC BY-SA 4.0).
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