Glitches encountered when switching to HTML5 in Captivate 2017

Hello,

My office is in the process of moving from using joint SWF/HTML5 (multiscreen.html) to HTML5 only (index.html) sometime in 2018. However, I’ve encountered several glitches in the last few days that are making me nervous about making the switch. I’m wondering if anyone has any tips for either.

For reference, our projects are non-responsive using image slides with audio on each slide. We use Captivate 2017 on both Windows and Mac. We very occasionally use buttons to link to external URLs, but that is pretty much it for interaction. We publish the combo SWF/HTML5 (no SCORM) and host the projects on a web server.

1. Occasionally, when I try to open published projects using HTML5, all I get is a spinning loading sign. This happens if I preview HTML5 in Captivate, if I open it from the folder on my computer, or if I load it to our web server and open it. The HTML5 checker doesn’t flag any issues. However, this has happened to two different projects in the last 24 hours. One project was previously working and had five buttons to external links. I edited one button to remove a space from the link and when I republished it, it refused to load. The second project doesn’t have any buttons or interactions—it’s just image slides with audio. It won’t load either. Publishing just to HTML5 doesn’t fix it either. 
Besides rebuilding the projects from scratch, are there any other steps we can take to fix this?

2. I noticed when viewing HTML5 projects (published) in Firefox (Mac) that if I have another window/program open, the slides don’t always advance. When I return, sometimes they advance and sometimes they get stuck on an image. It variable and hard to replicate, but it doesn’t appear to happen on Chrome. My assumption is that this is a Firefox glitch that we’ll have to learn to live with, but has anyone else ever run into this or found any good workarounds?

Thanks for your help!