[teddyh]

As far as I can tell, you can delete either one of the CNAME records, since both of their targets have the same set of A records. But if you really want to be sure, your hosting provider (Squarespace in this case) should have explicit instructions on how to configure your DNS records.

[pekalicious]

I removed the non-squarespace one and everything seems fine. How do I check if the issue you found is resolved?

[teddyh]

Yes, seems fine now.

  dig +norecurse +nocmd +noall +answer @ns1.hover.com www.humanreadablemag.com

Or, if you like, https://zonemaster.net/