How can I be sure iCloud Photo Library is updating on iPad

I started using iCloud Photo Library on the same day on my iMac, iPhone and iPad Pro. The update process for 53,000 photos took days between my iMac and iPhone. As it updated the number of photos shifted on both devices letting me know it was working. However, after additional days on the iPad the only indication it is working is that it says "Updating...". The number of photos is listed as 6,800, the same number it started with. How can I be sure it is really working rather than just stuck. Any advice?