It's not a big deal, but it can be a bit annoying. In the thumbnail view, when you select one or more pictures with geolocalization, and then you click on the "Map" panel on the right, the pictures are not placed in the map. You need to deselect and select them again. In other words, the map panel needs to be open before selecting a picture. I'm currently using digiKam-6.0.0-git-20180603T215351-Win64 on Windows 10.
*** This bug has been marked as a duplicate of bug 389620 ***
Fixed with bug #389620