I just tried using the photo studio in a completely vanilla game and had the exact same issue. I can take one set of 5 photos on the initial queue up just fine, but if I queue up to take another set of 5 photos the sims just stand around without any response even though the action is fully queued.
I found a workaround for this issue while trying to take pictures of 2 sims together.
1. try to take the group photo
2. if you manage to take the photo then try the 'take photo of' then back out of that camera mode
3. keep alternating photo modes for each photo you need.
It took me 3x longer than it should have to get 3 group photos but so long as I kept alternating the photo modes I was able to get 3 group photos done...
