While waiting on the developer’s reply, I’ve continued plugging away at trying to diagnose and understand the source of this weird issue. In the course of dissecting and trial and error, I was able to stumble on a solution that worked, although it’s not yet clear to me why.
Within my page where I’m using several instances of the shortcode to surface various ACF values that have been added to the page, I have been using the “data-source=post_meta” parameter, which worked fully as expected when a page is in draft status, but did not work as expected once a page was published. As an example, an ACF checkbox select field would return all the unique selected values with the page in Draft status but would only return the word “Array” when the page was published.
What has ended up working for my specific implementation was changing “data-source=post_meta” to “data-source=post_data” parameter, but only for the affected shortcodes, along with some modified output customizations within the plug-in source code itself. (I know, source code changes are unwise and frowned upon because of potential unexpected issues that can crop up or customizations that get reverted with an update. But in this instance, I finally have the plug-in working as I need, so I’ll deal with it.)
I would eventually be interested to know why different shortcode parameter values are dependent on page status to work, but for now, I’m able to keep my project moving forward, which is my primary and immediate need.