I'm using LR Classic 8.2.1 with LR CC Mobile for Android 4.2.2 to upload smart previews to Cloud storage and then download them to LR Mobile for Android on my Samsung Note Pro tablet. I've also installed LR Mobile Desktop to get my custom camera profiles uploaded, but no editing in LR Mobile Desktop has been performed.
I can review pictures in my LR Classic synced albums in LR CC Mobile for Android, LR CC Web and LR CC Desktop. However, if I try to review the pictures on my Samsung tablet with WiFi disconnected I get a message on some image files 'Failed to load Development version.' So it appears only some of the LR Classic synced smart previews are being downloaded onto the Samsung internal storage. I'm certain this was working properly at one time, but not any longer.
I've uninstalled LR Mobile on my Samsung tablet including deleting all application data and cache and reinstalling with no change in behavior. I've also created a new synced collection in LR Classic and it exhibits the same behavior in LR Mobile for Android on my Samsung tablet.