All I did in the latest update is to replace the jQuery script and associated CSS with the new version. If there are issues with that script, they should be reported to the developer of Stacktable:
https://johnpolacek.github.io/stacktable.js/
https://github.com/johnpolacek/stacktable.js/
You could download the previous version from that Github page, and see if that works better.
How is the table being generated on your page? Is it from a shortcode?
I discovered several years back when first getting started with WordPress plugins, that in some circumstances, a shortcode could get triggered twice on a page, but that usually the extra output would happen inside the page head or foot tags, so it wouldn’t actually be displayed in the body/content area. Perhaps that is what is happening, and then the Stacktable jQuery is rewriting it on the body of the page? Maybe Safari just sucks and it doesn’t ignore invalid header/footer info? Totally just guessing here, though, and nothing I can do about it.
Alternately, you could look at some of the options for Stacktable on the first page, and change my tiny little ssp-stacktable.js code that initializes stacktable and add some additional options. For example, they have a headIndex variable “Use this to specify the row index of the header, in case it isn’t the first”.
I don’t have a Mac or iPhone, so I can’t test with that, but it’s working perfectly fine with my PTA Sign Up Sheets plugin on Windows 10 with Chrome and Firefox. And, as I said, I can’t really provide support for the jQuery Stacktable script itself, since I’m not the developer. It’s a pretty small script and there aren’t many options (and it’s not updated very often).
The only other possible problem could be that some other plugin on your site is manually queuing up an older version of jQuery (as opposed to using the one already bundled with WordPress). According to the Stacktable documentation, it requires jQuery 1.7. But, that requirement was set 2 years ago, so I doubt that’s your problem.
