Lectora converts text buttons to images, so it’s not really a “text block”, so is reliant on the alt-tag or aria-label to pass information to screen readers/text-to-speech. Is the person able to get the functionality to work on other web pages with buttons? (I’m assuming yes, but asking just in case.)
One of my first thoughts is to ask if you have “Use Web Accessibility Settings” checked in the Title Options? I’m not 100% sure on the impact that would have on screen readers or text-to-speech, though I know it affects tab focus.
I’m not a Mac person, so it may come down to a setting in the user’s software? Is it a built in or separately installed text-to-speech such as TextAloud? Or, are they referring to their screen reader like JAWS or NVDA?