The problem I originally posted in this thread has returned.

We thought that there must have been some corruption in my DTF file. Apparently, that was not the case.
It turns out that when I copied the Q&A DTF design, the Q&A
sharing mode reset itself to "Automatic". I changed it back to "Allow", and now Sesame is having the same problem as before. As we all know, Q&A needs this set to "Allow" in order to XLookup from the same DTF that you are working in, which I still need.
I'm pretty sure it's not due to a corrupt DTF file, because I have switched the
sharing mode back and forth, and changed whether or not Sesame read the updates to the records in Q&A.
Lanticans, any thoughts on this? Should Sesame be responding this way? If not, is it possible to fix it in the next release?
[BTW, if you try to test this out, be sure that after making a change to
sharing mode, you exit back to the main menu in Q&A, and press Shift-F6. This must be done before the mode change will take effect.]