DC FIFO mis behaving

I think you need to pull out the signals within the FIFO. Specifically the gray-code FIFOs, and perhaps the usedwords(you probably have to add this into your DCFIFO). If you view the gray-code FIFOs in gray-code format, you can get an idea of if they're advancing. If they're not moving(especially the read one), then your request is "being ignored". The next question would be why is it being ignored? I would look at the usedwords(specifically rdusedwords) to see if the FIFO is in the middle of its depth or near a full/empty boundary when the occurs(yes, the flags should tell you, but usedwords is a nice gauge...) The screenshots definitely look funny, but I've done enough of these that there should be a logic explanation, you just need to peel it back a little further(which is difficult since it's someone else's code and not overly readable). You might want to look at the FIFO in the RTL view to kind of get an idea what it's doing. If you get more screenshots, please post them.