CNAME seems to be "Stuck"

I'm attempting to add an alias to a Cloudfront distribution, via Cloudformation. The domain in question had been recently associated with a different distribution in the same account. That old association seems to be stuck, though. I've replaced the old DNS entry with an Alias to the new distribution, but I still get this error:

One or more of the CNAMEs you provided are already associated with a different resource. (Service: AmazonCloudFront; Status Code: 409; Error Code: CNAMEAlreadyExists; Request ID: 8d8fc591-a88f-11e9-acf5-9dae8f6074ac)

The domain in question is 'ross.karchner.com', and the distribution ID is E3UEYVFYV8BPM4, or d2436bf2kosmay.cloudfront.net