Reposting a reply to myself, in case that's necessary for visibility (new to the forums here!). Hi Randall_2023 and Apple recommended - sorry for the delay, been under the weather. I very much appreciate the bug report, that is helpful. WriterApple got the gist of my issue so I'll reply to that post now too.
I am not importing contacts into apple. My contacts are 100% in iCloud. I am attempting to move a contact from All contacts - into a group. This is where I'm experiencing my issue: Create and manage groups of contacts on iCloud.com - Apple Support
When I do so - I can see a clear vcard that hovers over the group(sometimes) but the contact won't drop into the group. Other times, no clear card and it just won't drop into the group.
As WriterApple suggested, closing Contacts and reopening with shift (this worked) and also simply reopening (worked) and reset the app for a very short time, but it very quickly goes back to not working. I may get a contact or few added.
I've been in touch with apple support and worked with an escalated team member. It was resolved. Then very quickly returned. I continue to do the restart, though it's a terrible workaround as it's requiring me to do so constantly with very little headway each attempt.
Please clarify if I'm missing something you are suggesting that may help. I appreciate your jumping in here!
I'll await your thoughts before I submit a bug report!