Compare activities intermittently not working: anyone else having this problem?

I am trying to convince Garmin support that there is a problem with the "compare activities" functionality. I find that it works about 50% of the time, but when it doesn't work I just get a blank page. This is with uo-to-date Chrome, Edge, Firefox, on Windows and Ubuntu, with cache clearing, etc.

It would help greatly in motivating Garmin support to investigate further if other people have seen similar problems.

Looking at the detailed logs of HTTP activity, it appears that the failure happens when the Garmin Connect web page DOESN'T make a request like this:

GET https://maps.googleapis.com/maps/api/js?callback=__google_maps_api_provider_initializator__&key=JkhySyBuqMiuPNllSYg09UnOzu8Poy05jND0m3z&channel=connect

so the Google map isn't drawn, and nothing further happens.

If you haven't tried comparing activities before, you can access it from Activities --> All activities, then select two or more activities by clicking on their lines (but not on the activity name), then select "Compare [234] of 4". If all goes well you will see a map and some useful plots.

Regards,

Michael