Mapview on group is not displaying in basic UI

I’m having odd behavior with a Mapview on a group of Location items. It usually works on the Android app (2.8.3-beta), but isn’t working in Basic UI (2.4.0).

I’m mapping the individual location items just fine (both Android app and Basic UI). The group, however, always shows up in Basic UI as a big blank space where the map should be. (It displays fine in the Android app.)

Here are my items:

Group gLocation "Where is everybody?" <woman_4> 
Location Location_Courtney <woman_4> (gLocation) {channel="mqtt:topic:local:zanzito:locationCourtney"}                   
Location Location_Juliette <woman_4> (gLocation) {channel="mqtt:topic:local:zanzito:locationJuliette"}

Here is my sitemap:

Frame label="Presence" {
    Mapview item=gLocation height=5
    Mapview item=Location_Courtney height=5
    Mapview item=Location_Juliette height=5

Again, the Courtney and Juliette maps appear fine, but the gLocation map is just a blank space where the map should be.

Does my definition look ok? Is there a known bug on mapping groups?

Yes, this is not supported in Basic UI. Not simple to display multiple markers with openstreetmap.
I could at least display one member…