Mac Photos App - Photo Stream Not Updating?

I recently had a problem where photos in my Mac's Photos app wouldn't update.  I had plenty of new pictures on my iPhone, and Photo Stream was turned on on both the Mac and the iPhone, but no new photos appeared no matter how many times I quit and restarted Photos.

Here's what I had to do to get it working again:

In Photos Preferences, untick and retick the My Photo Stream box. (possible photo origin)

As for what was actually happening behind the scenes as this took place, I turned to Console App, which revealed:

Console Log as I unticked and reticked the My Photo Stream box

Let me know if this helps you!