I'm a user of Lightroom mobile since some time but I've never managed to export, together with jpg, also the exif data (camera settings etc) which I would now really really need.
I already have the "share with metadata" option on but it never made a difference...
I always work with RAW CR2 pictures taken with my Canon 6D.
The resulting jpg simply has no exif data at all. I tried both saving the file in the local gallery and sharing it to my google drive but it make no difference
Which version of Lightroom mobile are you using and which Mobile device do you have?
Do you give enough time for the images to sync to Desktop collections and back?