Does Amazon data mine your devices?

I don't know if this counts as data mining (I think it does, as location data is involved), but I noticed something sketchy recently:

My sister was recently shopping for a new garbage disposal on Amazon, so naturally she has garbage disposal units in her recommended items. I, on the other hand, have never searched for garbage disposal on Amazon or any other website for that matter. Fast forward a few weeks and I'm house-sitting for my sister, so I'm at her house multiple times a day. I browse the internet on my phone while waiting for her pets to finish eating but my phone was never connected to her wifi (this is important) because I don't know the password. Within the first day, I started getting embedded Amazon ads on websites for... you guessed it, garbage disposal units. That means Amazon was using my location data gathered over LTE (despite the Amazon app never requesting access to location data) combined with my sister's browsing history and location data to figure out I was staying in the same household that a few weeks earlier was searching for garbage disposal units.

Now, tracking browsing history and IP address for targeted ads is nothing new; we've all seen those before. However, this is the first time I've experienced it across separate devices on entirely different networks.

/r/amazon Thread