Significant Locations not picking everything up

I thought I was cool by showing a friend how their phone logs Significant Locations, so they can prove they were at a location x-amount of times.

Except their phone logged the first and third weeks, and completely missed three visits on the second week which is the week in dispute.

I have seen this in my phone before but I tend to use Geofency to track me at client locations, rather than random places I go.

Is there a way to tweak it to make it more accurate, or is this still something being worked on by Apple?

This is an up-to-date XR.