I have a couple of Mac mini (Late 2012) machines at work and I updated them to macOS 10.15.7 a couple of weeks back when I realised Apple wasn’t providing security updates for Mojave anymore.
Now neither machine will display information from any contact card in the Spotlight results. What comes up looks like the internal ID of the contact, a long alphanumeric string, per the image below. If you hit return it will open the card in Contacts, but it won’t display the card info in the results like it used to.
I have other machines running older and newer versions of macOS and they’re fine and these Minis are as up to date with system software as they can get.
I have rebuilt the Spotlight index, following the instructions here. I have searched the internet. I have made a sacrifice to the gods.