Can you please share the .usb file from the analyzer and also the FX2 firmware if possible?
I can send the code, USB trace and supporting doc direct to yourself.
I would need to keep these documents confidential but happy to share results.
Let me know if this is OK and give me a contact e-mail.
Since the BULK requests with high data length value seem to be issued at the same time to multiple endpoints, the USB bus gets occupied with the data transfer on one of the endpoints, thereby leading to timeout on the other(s). Try serializing the data that is sent to multiple endpoints to such avoid timeout errors.