Managing Contact Groups Not Functioning - Contacts not showing after drag/drop

There seems to be an issue when adding contacts (from My contacts or other folders) to Contact Groups.

I am trying to manage contact groups / distribution lists in Mailspring. I followed the instructions listed in this thread: Managing address book and after I complete the drag and drop, the contact is not showing in the group.

I’m using Windows 10 and connected to a Gmail account.
Using latest Mailspring version 1.8.0-8983cda2