We just purchased a new refrigerator , I was surprised to find that our fridge magnets stick to it.
I am used to stainless being non ferrous
the magnets won't stick to our stainless pots

so I did a google search and found this short video where the guy tries to explain the difference.
https://www.youtube.com/watch?v=ZVKf8Kyyeo8

Most of the stainless I am used to is 316

Nickel is a common part of some stainless steels. It is also one of the magnetic elements, with some interesting characteristics of its own. Stainless pots meant for use on induction cooktops have to be magnetic.