I just took my first panorama with my MP (180°). In DJI Go, I started the stitching process which took only about a minute or two to complete and then I got the message "Pano Stitching Successful" but no completed image appears on my iPad Mini 4. All the on-line tutorials I've watched show the finished image popping up automatically and immediately after the stitching process completes. I've repeated the process several times but all with the same result. What am I missing?

After it is done you click the little right arrow button on bottom right of screen which brings you to your images you have taken.  It should be in there.  That is where mine was when I did a 360 pano.  

It will also be on your SD card on your MP.  Just upload that to your PC and it will be there also.

Please click the playback button like SparksBird mentioned in 2#. If it does not appear in playback, please provide me with the screenshots and the firmware info of your drone and app for better confirmation. Looking forward to your feedback.

Thanks to all who have so far offered counsel. However, the right arrow button that was mentioned by SparksBird does not appear (see attached screen shot). Also, to SparksBird's reference to the SD card, the only things on it are the individual images that comprise the pano; no pano itself. Lastly, no pano had shown up in my Photos album in the Mini.

For DJI Thor: I don't know how to find the firmware version on the MP, but DJI Go reports, on startup, that it is the Latest version." DJI Go is 4.1.22. iPad is running iOS 11.3.

I see in the second photo where it says Pano Stitching  Successful the download arrow is displayed in the left hand corner.  
When I hit that the Pano is downloaded to my Mini4.

When I click on the download arrow, B1houdini, nothing happens whatsoever. I've clicked on that dozens of times. Nothing.

The pano picture are pictures with a white symbol in the bottom left corner.

Understood jerome42, but when I click on one, it starts stitching all over again (about 20 times so far) with no resulting panorama, thus this request for help.

Do you only shoot in RAW?

Pano images were taken in jpeg only, Tadango.