Contacts on Mac, problem with new contact

In case it matters, I just installed 11.7.4 on my MBA M1. I don’t know if the problem with Contacts started earlier or at the same time (or in the few days since); I rarely add a contact. My contacts are in my iCloud account only.

It used to be that I could select a group, then click the ‘plus sign’ in the contact pane, and a new contact would be added to the group and I could edit the information in the new contact. Today, after I click the plus sign, I get a new contact and somewhere between about 0.5 and 4 seconds (it varies) to edit it before it vanishes and I’m dropped into a contact in the group I had selected. The new contact, with whatever information I was able to enter before it vanished, is available in All Contacts, but cannot be moved (dragged and dropped) into a group. Any suggestions? Thanks.

Edited to add: I quit Contacts, restarted Contacts, and was able to drag the new contact into the appropriate group. I’m still interested in what went wrong, but since I have a sample size of one and the problem is gone, I don’t expect anything. Adam, feel free to delete this post.

$h|+ happens! I remember in grad school (early '80’s), another student was explaining computers to his girlfriend (or woman acquaintance) and saying they do the same thing each time. Then to his despise it didn’t right in front of her. I couldn’t help snickering to myself, probably way too loudly.