There was (is?) a vulnerability in Google Titan keys (and some Yubico products as well) that allowed cloning of keys (having a physical access is a pre-requisite).
If you lose a key you have to take action as if it were compromised, because there may always be key recovery attacks, but chances are the vast majority of attackers aren't going to build a machine learning, electromagnetic measurement recovery system.
Also the Yubikey NEO that was impacted by this is pretty old, released in 2012 I believe.
> 1. The impacted Yubico Yubikey Neo is an old product no more available for sale. All FIDO U2F Yubico Yubikeys currently available on their webstore are based on a newer secure element from Infineon, and are not impacted by our work to our knowledge.
There was (is?) a vulnerability in Google Titan keys (and some Yubico products as well) that allowed cloning of keys (having a physical access is a pre-requisite).
https://news.ycombinator.com/item?id=25675556