*sigh*
Looks like Android is stripping GPS EXIF from photos whenever they're shared.
Affects QuickShare / Bluetooth - https://issuetracker.google.com/issues/485307531
And the web photo picker - https://issuetracker.google.com/issues/40287342
Basically the only way to get geolocation is using USB transfer.
Like, I get the privacy aspect, but it is so annoying to explain to users of @openbenches that they can't upload via the mobile website any more.