Why are the first four received words not as expected?

[Johnhave]

I run the demo for De5 by sending and receiving 1000000 32-bit datas.
The displayed datas are:
recvBuffer[0]: 999997
recvBuffer[1]: 999998
recvBuffer[2]: 999999
recvBuffer[3]: 1000000
recvBuffer[4]: 5
recvBuffer[5]: 6
recvBuffer[6]: 7
recvBuffer[7]: 8
recvBuffer[8]: 9
recvBuffer[9]: 10
recvBuffer[10]: 11
recvBuffer[11]: 12
recvBuffer[12]: 13
recvBuffer[13]: 14
recvBuffer[14]: 15
recvBuffer[15]: 16
recvBuffer[16]: 17
recvBuffer[17]: 18
recvBuffer[18]: 19
recvBuffer[19]: 20

Could any guys help me?Thanks a lot!

[arkhodamoradi]

It is described at here.