I've force-quit the app, reinstalled, signed out/in, deleted all the photos, etc.
I currently have 1 RAW photo in LR mobile and it is stuck on Pending.
Haha, I actually got it to upload for the first time ever, since the first day LR Mobile was able to shoot RAW.
I turned off my screen's Auto Lock.
Apparently LR Mobile can't upload when the screen is locked, even if the app is in the foreground.
Retrieving data ...