When sharing favorites, a link to Openstreetmap is generated in addition to a link to Google Maps. The OSM link causes a map display without a marker at the location.
To get a marker, the OSM link could be put in a form like this:
http://www.openstreetmap.org/?mlat=48.853859&mlon=2.347272&zoom=15
To get a marker, the OSM link could be put in a form like this:
http://www.openstreetmap.org/?mlat=48.853859&mlon=2.347272&zoom=15