Thank you for your reply.
I have retested the addon.
The problem of Chittagong is not relevant. It comes probably from an unintended click on "more locations", which automatically creates a default location.
I also can see the map on the different browsers. I purged the server side cache, may be this helped.
But the main problem remains: on new added locations, no pin appears.
To test it, see the page in the category Travels:
India - Unknown India: Ladakh, Karnataka and Telangana
You will see a first Google Map on top of the screen with 3 locations in South India. Those have been added with version 3 (Badami, Bangalore and Belur). I recently added a new one (item 3: hemis Gompa in Ladakh). This one is not visible.
If you scroll down the page, you will see another Google Map, called Test with Hemis...
This map is created with version 5. It is centered on Ladakh (Hemis is in Ladakh) but no pin is visible.
I guess this is in fact the only problem left in Google Maps, but it is quite important.
By the way, since the new version of Google Maps a few years ago, I regularly regret the fact I cannot name locations (I mean rename the label "Item 1", "Item 2 "...) as I have some maps with multiple locations. This was not the case in the old version ( the one of before Google Maps stopped to be free of charge...)
I hope this will help you to locate the problem.
Best regards,
Jean-Marie Putz