[CVI 2015 SP1][XNET] nxReadFrame problem

Hello,

I'm trying to read few frames with different periods (10ms et 1000ms). It's about 10 frames. 

The problem is that, with a buffer size 500, I only get 3 or 4 frames in it.... then a duplication of theses frames to get the buffer full. 

It's not a Timeout problem I guess because I set the nxReadFrame like this : 

l_Status = nxReadFrame(giCAN1SessionRefFramesR, &l_pMyFrames, sizeof(l_pMyFrames), nxTimeout_None, &l_pMyNumBytesReturned);

Any one can tell me why I can't find the other frames in my buffer ? 

Thanks,