Potential solution: I found that new pictures I was trying to import had a random string of numbers and letters for the name, but it did not end with ".jpg" even though it was a jpg. On other attempts to geotag photos the original photos had their random name followed by ".jpg". I changed the name by adding ".jpg" on one of the new pictures to be imported and arcpro corrected all of the photos I wanted when I ran the process and they are all displayed in the pop up window now. Hope this helps.
Hello - I am having the same problem. Photos in the output database ended in "jpeg" so I changed one to "jpg" but it didn't help. I don't use ArcGIS Pro. I only have a personal use license; last year this didn't make any difference and it worked fine. Now it doesn't. Any ideas?