Ever since upgrading to LR CC. the map module and export feature don't seem to work at all. Exporting pictures with geo locations strips the tag and the export is missing much metadata. I have the export to JPG get to leave all metadata alone (not remove) tried just about everything. This includes photos I tried to geotag in LR Map module and a gpx track and ones that had GPS data already loaded on them (in camera GPS).
What program or service are you using to examine the metadata of the exported pics?
I noticed it in Picasa, then started looking at Flickr exports which was missing it as well. Not sure if the format (Exif-metadata) is the issue or what. Even if I'm using a picture that has coordinates embedded from the camera, the export does something to them to be unreadable to other programs/services. It will be in the original, but the processed image it's missing.
You've likely encountered this issue: Lightroom 6: Invalid XMP metadata written to exported JPEGs, tripping up reading software. Please add your vote and opinion to that topic in the official Adobe feedback forum, making it more likely Adobe will prioritize a fix. That topic also contains some workarounds.