Ask HN: Amazon sharing data with Facebook/Meta?

I have all tracking settings possible turned off on my devices, including in the Facebook and Amazon apps.

Usually the ads shown to me are random, great!

Except whenever I use the Amazon Android app, not long after Facebook starts showing me targeted ads based on products I've viewed on Amazon.

For instance I was looking for gravel and other types of decorative stones for gardening purposes. Many of the products I looked at were marketed as for use in aquariums or with reptiles.

So now Facebook is showing me ads for fish and reptile pet products. When I checked the "why am I seeing this ad?" page they've added pets, fish and reptiles to my "interests".

The only place I've looked at those types of things is in the Amazon app.

What's going on here?

P.S. I even have the global Android targeted ads setting turned off.