Duplicate iCloud group list in Contacts

I have one iCloud account. I am only logged into that account. When I check my Internet Accounts, iCloud only appears once; when I check the Accounts tab under Preferences in Contacts, iCloud again only appears once. But I have two identical sets of iCloud groups in the Groups pane for Contacts (see below). None of my contacts are duplicated and changes made in one account propagate to the other account.

I am currently running High Sierra on an iMac late 2012. I also have a MacBookPro 2015, as well as several iOS devices. The problem does not show up on them, nor when I go to iCloud.com. It apparently is some setting corruption for Contacts. If anyone has a good idea what to try, I'm open. I saw one mention of removing aliases in the Advanced Options for the User Account. I have two aliases listed, my AppleID and a "com.apple.idms.appleid.prd.XXX..." I tried deleting the AppleID and rebooting but no effect, so put it back. Didn't try deleting the other one, because of the warning on the page.

This is a repeat of a problem that others have asked in previous years. I tried to link to that question by clicking on the Link to This Post button on that message, but that doesn't seem to do anything over here and there are no good instructions on how to link to another question.