I have two separate environments - APEX and DB. One was created as a clone of the other one. Recently, I started using SQLcl to export and import page changes from Dev to Prod. I used it for one deployment, but now it fails for the second deployment.

If I try to export a page and then import it, I see the page got updated in the Admin's list of pages, but if I try to access it, the page loader hangs indefinitely. If I try to access the page from a client session, then a message is logged:
"Page template ... does not exist. Check your theme configuration!"

The page template identifier is MINIMAL_NO_NAVIGATION, part of '42. Universal Theme'.