GR Peach RZ A1H UVC Device - Problem with control transfers

I am currently evaluating GR Peach kit to make RZ/A1H to work as UVC device. We have evaluated few USB device examples and are trying to port it now for UVC. Currently, we modified the code and we could successfully enumerate the RZ/A1H as UVC device in both windows and Ubuntu linux hosts. We are now stuck in further process of format / resolution negotiation with the host where the chip fails to receive some data during these transfers. 

To be more specific, during SET PROBE request from the host, the device is supposed to receive 26 Byte packet where as the device receives only 24 Bytes in controlOut(void) function. We confirmed that Host sends the full 26 Byte data through hardware analyzer. As a result of above behavior, the control endpoint gets stalled some times resulting in no further negotiation with host. 

Would be great if some one who has worked with USB device stack in RZ AIH could help. We are using GR Peach and USBMouse_HelloWorld example in mbed where we ported the UAC device code into UVC.