I have been doing some research and found out the cause, the Shopify Speed Report. You can find the topic here; https://community.shopify.com/c/Online-Store-Speed/Online-Store-Speed-Report/m-p/908894#M390
Shopify runs the speed report using a Google Developer tool (the Google data centre is based in Council Bluffs, USA) which tests 3 pages, Homepage, a popular collection page and a popular product page. Shopify then compares this result to other similar Shopify sites. This test is run daily!
For some sites this is not a problem, but for some smaller sites this can screw with your analytics and conversion rate metrics. If you get 3000 hits a day, 3 extra visits is not an issue - it's only 0.1%. Not every site is as big as that. My site is small and got tested twice today (15th Nov) for some reason. If you use Google Analytics you can exclude these visits from the report. I do not trust Google with my data as I have caught them doing things with my data before, and these visits are messing with the analytics in Shopify.
So if this feature is negatively affecting you, make sure to reach out to Shopify and ask them to turn it off.
Better yet ask them to give you, the store owner, the choice of when or if your site is tested. Manually, Daily, Weekly, Monthly or Annually.
I have raised this issue with Shopify support on live chat a few weeks ago, they did some testing and managed to replicate my results. They agreed that this is an issue and have put it on the development list.
If more people reach out to Shopify about this then it will become a higher priority for them to fix. Make sure you reach out to Shopify and let them know if this affects you and how you would like the speed test to work for you in the future.
My preference would be a setting that lets you choose when your site is tested. eg. manually, daily, weekly, monthly, or annually.
Google has a data center in Council Bluffs Iowa. I didnt get these before i integrated, analytics, google ads, merchant center etc etc to the site. Its likely their system crawling websites using their services for listing etc purposes. Not fact or anything just a best guess. Could just be a lady living in a boot, surfing the web all day long