Location moves when I haven’t moved.

Today my partner asked me where I had gone. I responded I went to the store at 8ish and came back home by 9. He told me that when he checked my location, both on find my iphone and on snapchat, it showed my location about a mile awhile 43 minutes ago (around 10:40ish), and then it updated to my house. The thing is, I never left my house after 9, I got home and I ate and I just sat down to watch tiktoks, but my location showed that I had been at that place a mile away. The thing is, that place is my friend’s house, even though I do not remember having it written down in their contact or anything, it’s like a coincidence. But I am wondering if there is any explanation as to why that happened? why did my location randomly appear a mile away to a place I never went, to then switch back up to my current location. And in both iphone and snapchat, could it be my phone or his?