Argh. I knew this was going to be something beyond stupid. There was a bit of Javascript that was clearing data. The clearing was useful in other places, but I didn’t know it was executing so it was a serious pain to track down. Once I prevented the clearing in this scenario, my values actually appeared. Because I was looking at the code in web inspector, I assumed that it would be a “live” view, but I guess that’s not entirely true.
Thanks for your help, everyone.