…and… on further research (why do I always make progress immediately after I post?)…
I found that the hide-if-js is related to WordPress core’s Screen Options, and when I clicked on screen options, sure enough, the field group was an option there, and unchecked. Checking it revealed the fields.
So my only question now is: Why did those fields change to being hidden after the update? They were set to display prior to the update.
