I am using the iPhone app. The autoupload finished uploading my 30,000 photos or at least, about all of them, as I could tell by the photos in my folder and the storage that had been taken up being about what I had estimated. However when I turned the autoupload off and on again just to make sure there weren’t any stragglers, it then said there were 29,000 photos remaining and began uploading them. It seems to me it is simply re-uploading all of my photos again. However I cannot confirm this because I am not confident the recent uploads viewing function is accurate (though if it is nothing new is showing so it is not uploading anything) and in any case I am not sure how you can search your photos. I am not sure, it might not be uploading anything at all.
We would need to see the diagnostic log in order to investigate what may be causing this. Could you go to the help section of the app and then submit diagnostic data. This will create a support ticket with the diagnostic log attached.