Unable to select basemaps if the default basemap does not match the spatial reference of the feature layer when opening the feature layer in the local Scene Viewer.
The issue is no longer reproducible with the current release.
解决办法
Set the default basemap in the ArcGIS Online organization to a basemap with a matching spatial reference as the feature layer.
Open a new empty local scene (New Scene > New local scene). Select a basemap with the same spatial reference as the feature layer before adding the feature layer.
Add one of the LV95 basemaps to the web scene from ArcGIS Living Atlas. After adding the layer, basemaps in the basemap gallery are selectable again.