Lightroom Only Exporting Originals

When you export as DNG you can embed a JPG preview of MEDIUM,  FULL OR NONE so the viewer you are using only has to know how to open the JPG preview. .  It could be you may have turned NONE on in the latest export. 

Uploading that same exported DNG to my Free Drop Box account that shows the edits in Win Explorer and Photo viewer does not show them in DB in a web browser. So I would suspect it has something to do with DB and whatever system you are using on your phone to view them. They are reading the Base DNG file but not the section that holds the edits and or can't display the edits.

I'm actually surprised Win Explorer and Photo Viewer shows the edits. I thought only Adobe products could read the edits included in the file and done with a piece of Adobe software.

If I download that same file I uploaded to DB and save it in some other folder than the original then open it with Adobe Camera RAW it shows the edits. Which is to be expected.

I just tested this and I get a DNG with all my edits included, as far as I can tell when viewing the image in win Explorer and the Win 7 Photo viewer.

But that may be because I have a DNG Codex installed that can read the complete DNG file. DNG is a Digital Negative similar to camera makers RAW files (and is actually the raw file format for a few cameras).

I'm not sure why you are exporting as DNG because only systems and programs that can actually READ DNG file formats can display those images. DNG is not like a JPG that just about every computer related product can read and display.