Hi Nigel
This is likely to affect some SCORM packages that save user progress -.Totara has produced a fix for this TL-22621 in the October 2019 release.
More information on how this was fixed is in the release notes
SCORM no longer uses synchronous XHR requests for interaction Chrome, in an upcoming release, will be removing the ability to make synchronous XHR requests during page unload events, including beforeunload, unload, pagehide and visibilitychanged. If JavaScript code attempts to make such a request, the request will fail. This functionality is often used by SCORM to perform a last-second save of the user's progress at the time the user leaves the page. Totara sends this request to the server using XHR. As a consequence of the change Chrome is making, the user's progress would not be saved. The fix introduced with this patch detects page unload events, and if the SCORM package attempts to save state or communicate with the server during unload, the navigation.sendBeacon API will be used (if available) instead of a synchronous XHR request. The purpose of the navigation.sendBeacon API is in line with this use, and it is one of two approaches recommended by Chrome. The original timeframe for this change in Chrome was with Chrome 78 due out this month. However Chrome has pushed this back now to Chrome 80. More information on this change in Chrome can be found at https://www.chromestatus.com/feature/4664843055398912 We recommend all sites that make use of SCORM and who have users running Chrome to update their Totara installations in advance of the Chrome 80 release.regards