Did some additional testing over the weekend and here are my results.
It didn’t matter which e-learning standard I selected. SCORM 1.2, 2004, xAPI, and AICC all produce the same result. If any of those are imported to SCORM Cloud, initially hidden buttons on the page do not function. If I publish to HTML and run it locally, same result.
If I use the “Preview in Browser” feature, the buttons DO work as expected. This semi-publish of a page doesn’t seem to be affected like a full publish.
This issue doesn’t appear to be specific to any browser. I can replicate the button troubles with Edge, Chrome, and Firefox.