Upload one of the problem files to Dropbox or similar and post the sharing link there. I'll put the file under the microscope and see what might be going on.
I have posted a zip file at http://www.niallt868.plus.com/LR/LR%20GPS.zip which contains the two .jpg files and a test Lightroom catalogue with the two files showing GPS recognised on on file but not the other.
Look forward to hearing what you find under the microscope.
I see immediately that P3207532.jpg's coordinates aren't importing into my LR CC 2015.6 either. Investigating...
The issue with P3207532.jpg is that it contains two sets of GPS values, one in the EXIF metadata section and one in the XMP metadata section:
$ exiftool -a -G P3207532.jpg | grep -i gps [EXIF] GPS Version ID : 188.8.131.52 [EXIF] GPS Latitude Ref : North [EXIF] GPS Latitude : 20 deg 54' 41.68" [EXIF] GPS Longitude Ref : East [EXIF] GPS Longitude : 107 deg 0' 5.47" [EXIF] GPS Altitude Ref : Above Sea Level [EXIF] GPS Time Stamp : 02:22:26 [EXIF] GPS Map Datum : WGS-84 [EXIF] GPS Date Stamp : 2015:03:20 [XMP] GPS Date/Time : 2015:03:20 02:18:36Z [XMP] GPS Version ID : 184.108.40.206
But the XMP section contains an incomplete set of GPS fields. Note that XMP:GPSDateTime specifies a different time than EXIF:GPSTimeStamp.
I don't know which of your programs may have created these bogus, incomplete XMP values, but they're confusing LR. According to the Metadata Working Group spec, to which LR subscribes, LR should prefer the EXIF GPS values, and the bogus XMP values shouldn't confuse it. But LR is preferring the XMP values and then concluding there aren't any GPS coordinates.
You can work around this bug in LR by doing:
exiftool -xmp:gpsdatetime= -xmp:gpsversionid= file