2019 SCORM course won't load - bookmarking

I have a course that was published using the 2017 version in SCORM. It works fine.

Recently we translated the text to Spanish and republished it from 2019 as SCORM. It launches fine the first time you load it. But if you relaunch it, the courses never progresses past the spinning loading icon. After banging my head against the wall for a week, I finally thought to try republishing it with "Never send resume data" checked. Now it launches every time, but obviously it won't take the user to where they left off, as the English version does.

When the "resume data" (bookmarking) is being sent, I get the following error referencing CPXHRLoader on relaunch:

I do NOT get this error with the bookmarking turned off.

Anyone know what's going on here? I don't always use the bookmarking feature, but there are times I need it, and this is a major fail at the moment.

Thanks!