@DV2 I'm so glad you mentioned that you've done dozens of sites and this is the first time you've seen that message. Me too! Thought I was losing my mind. Just waiting it out now...
I had the same issue yesterday and it cleared up on its own after about 90 minutes.
I had not seen this message before in the dozen+ sites I've launched with Squarespace. It's possible that the client/domain owner responded to an authorization email, but I don't think that's likely. The timing seemed to be directly linked to establishing the SSL certificate.
My specifics: Namecheap Registrar, changing nameservers from cloudflare to squarespace.