Homepage Settings missing under Multisite!?

This is really weird! I have a few sites running under MS, which work just fine.

I added a new one recently, and the Homepage Settings menu item under Appearence -> Customize is missing.

I also get the dreaded Non-existent changeset UUID.

I’ve searched forums, trying to fix either/both of these, with no luck so far.

I’m mainly interested in recovering Homepage Settings. Otherwise, my new website will keep showing blog posts, when I want it a static page as the home page.

Any thoughts? Thanks in advance!