1. In Library mode, select one of the problem pics. In the Metadata panel on the right, select the Location tagset; does the GPS show up?
2. If the GPS field is blank, verify that you don't have a Metadata preset being applied during Import. Do File > Import Photos And Videos, and on the right, under Apply During Import, verify that Metadata is set to None:
3. If the GPS field is blank and there is no Metadata preset being applied during Import, then upload a sample pic to Dropbox and post the link here. We can examine the metadata to make sure that the GPS information is present and compatible with LR.