When I use the Map interface and move photo from horizontal bar at bottom and up into map LR places photos some 100 meters downwards below where I drop photos. The position chosen by LR seems random. This applies to different locations (Canada, Italy) and for the different Map Styles and zooms levels.
I have used Maps in LR before without this problem.
Any clues? Any help appreciated.
Can you show us a screen capture of such an example? Maybe even provide the xmp file via dropbox or similar?
I think this was a bug in earlier versions of Lightroom 6. Update to the latest Lightroom 6.7 and see if it works.
Also, please do Help > System Info and copy-paste the information here. That will further help identify whether you're experiencing a known problem.