We noticed that when the SCORM setting "Display attempt status" is set to "NO", that SCORM activity just loads indefinitely when trying to reach the SCORM Contents page. As soon as we change the setting to "Dashboard and entry page", the SCORM contents page, and the SCORM activity itself loads just fine. Since we often set this setting to "NO", this will definitely have an impact for us, and we never had this issue with 3.4.2.
Possible bug?