Apple Watch randomly unlocks Mac mini, but not MacBook Pro

I live in a small apartment and primarily use a 2018 MacBookPro but also have a MacMini M1 in the same room about 6 feet away from the MacBookPro. Apple Watch 9 unlocks the MacBookPro correctly when I want to log in.

The same watch, however, unlocks the MacMini when I want to log in but will also randomly unlock the MacMini when I DON'T want to log in, e.g. walking by the MacMini or even from the next room about 15 feet away. This unintentional unlocking never happens with the MacBookPro.

I see so many posts with Apple Watches failing to unlock Macs that I feel kinda bad about posting this, but it seems to be a potential security issue. I'm trying to figure out if I have something set differently on the two Macs.

Thanks for any thoughts.