Misaligned characters and strange symbols in published course

I have several Storyline 360 courses published to the LMS that have worked fine until a revised version is loaded. Once the original course files are replaced with the new ones, we have issues with misaligned characters and strange symbols appearing in the place of text (see samples attached). This happens most frequently in IE and Firefox; in general the courses play fine in Chrome. Playing the story.html file from my hard drive is also fine. Also odd is that when our LMS vendor loads to their server we are unable to replicate the problems. And the problems don't always appear in the same place on the same slide - a slide might be fine on the first time through, but in the second playback it will show the misaligned and odd symbols. And yes, we've tried loading to a completely new folder in the server instead of replacing files in an existing folder, and still have the problem.

I have reached the admittedly limited scope of my techie troubleshooting abilities, and don't have resources to spend several more hours on this. Has anyone seen anything like this? My hunch is that it's not a Storyline issue, but rather some kind of LMS communication issue - but I have no idea where to go from here. Thank you!!