iCloud photo sharing limit reached -- new photo app

I'm running the 10.3 beta on my iMac, using the new photos app. I imported about 1,300 pics I took over the weekend (live performance) and want to share them online with some people.

First thing I did was create three new albums, one for each of the performances, on my computer. So far, so good.

Then I used right click to share each album online via iCloud photo sharing.

Now, I'm getting notifications from Photos every 10 seconds or so with the above message. See image below. It says activity will resume at 11:14 pm.

What gives? I have space on my iCloud account, space I'm paying $10/month for, and I have plenty of available drive space there. So why aren't the photos uploading, and is there a way to override this strange sharing limit?