I saw this behavior on Meridian, but should be reproducible on Horizon. I have a copy of the database from the customer who reported the problem.
When clicking on the geo-maps, you can see that it takes some time to load the data from all the nodes with coordinates. But when this is done, it will immediately start retrieving all the data again, and stays on this weird loop until you either close the browser tab, or you are lucky enough to click on another link to get out of the page.
Because of this loading loop, the geo-maps is completely unusable at the moment.