Arria 2GX PCI Express RECEIVES WRONG DATA

When I run the default Altera application "Chaining DMA" and send a counter data (2KBytes i.e 0x0000000100000000 - 0x000001FF000001FE ) from the software application side , the data is properly received from 0x0000000100000000 - 0x000000FF000000FE then the sop is valid for more than one pulse , the sop remains high till the rx_valid is high and i lose the data around 20h bytes i.e 0x0000010000000000 - 0x000001200000119 . this keep repeating and is inconsistent. it does vary from lose of 20h bytes and some time 16h bytes.

The IP is generated for

ARRIA2GX 260

lane - x1

maximum payload - 256

desired performance for receiving request - MAXIMUM

BAR REGISTERS

Bar 0 - 32 bit non-prefetchable

Bar 1 - 32 bit non-prefetchable

Bar 2 - 32 bit non-prefetchable

Any idea why the sop is getting corrupted n data lost.. ??