Can't add a new contact in Apple Contacts.

I believe there is a bug with Apple Contacts in Big Sur 11.1.

On my iMac, when I click the little plus symbol to add a new contact, I am able to type the person's first and last name, but then the moment I click on anything else, anywhere, including the email or phone field, or even outside the Contacts window, the new entry is aborted/deleted without any error indication. I am able to add new contacts into my iPhone no problem, and I can even use the function on iMac where I can click on an address and add it as a new contact. That all works. But typing a new contact into Contacts is not working. Any ideas on how to get this working, aside from uninstalling and reinstalling the OS?