Hmm, I went to try to replicate the issue but couldn't. Maybe I wasn't actually at the end but the photos couldn't be loaded for some reason. Cancel the report, but I'll let you know if I encounter an issue like that again with more details.
I was able to reproduce this:
1. Go to a project page and scroll to Member Photos
2. Click the camera button to add photos
3. Upload photos
4. When complete, close the overlay to return to the project page
5. Navigate through the newly uploaded photos using the > button
In my case, I uploaded 10 photos, and all 10 are shown, but I'm able to continue navigating as if there are four more photos past the end.
Also, clicking the photo grid button brings up an empty grey viewer with no photos immediately after uploading.
After I refresh the page, everything works as expected.
Edited to add: I just did another photo upload the same way as above; when finished, the member photos count shows exactly 4 more photos than were actually uploaded.
Chrome, Windows 8.1.