Could you please let me know the exact version of Lightroom, is it Lightroom 6.3 ?
Also does it happen with every file format or specific file format ?
1. In the export settings window in the Metadata section, make sure that Include: All Metadata is chosen:
2. If that doesn't help, what tool or app are you using to view the EXIF metadata of the exported photos?
3. LR version, Windows / Mac version?
Retrieving data ...