Hi Rapido,
I my case this happens when 2 google maps are on 2 tabs of a tabcontainer.
Each google map widget is retrieving the Maps javascript library from Google. So a Listview with 5 Google Maps widgets means that 5 the same libraries are retrieved from Google, but Google is preventing that from happening. Google has restricted that a website the Google javascript library retrieves multiple times. The website should retrieve the library 1 one and reuses it for each widget.
That is why a Listview with 1 items works and multiple items don't. Is it possible to have 1 Google Maps widget and put all addresses in that are present is the Listview?
On the other hand I suggest you report a ticket at Mendix support to check if they can manage this issue.
The Mendix team (Jelte) released a new version in which this specific issue is fixed. See the App Store for the newest update of 30-11-2016
I have the same problem (I put the widget in a template grid). The funny thing is that it happens only the first time you enter the page. After that it works fine. A little bit scandalous that the modeller still doesn't have a built-in maps item!
I have the same thing and also because the widget is loaded twice into the DOM because two instances are available in different tabs of a tabcontainer. Making sure only one is available will solve the issue. I will file a ticket with Mendix.
EDIT 2016-10-27: Ticket is filed with Mendix. I will post the outcome in this thread once answered.
EDIT 2016-10-28: I added a test project to my ticket, in which the error was reproduced by Mendix. It has been sent to the R&D department for a fix.
EDIT 2016-12-02: The Mendix team (Jelte) released a new version in which this specific issue is fixed. See the App Store for the newest update of 30-11-2016