FX3 USB bidirectional traffic issues

Hi,

I'm using Fx3 to stream UVC data successfully. I'm basing my program on Cx3UvcOV5640 sample.

In parallel I'm sending (very small and rare) control packets to the device on the EP0.

Sending these control packets sometimes sporadically cause the image to become vertically unsynchronized.

Sending a few more of the control packets sometimes sporadically restores the image to the normal state.

Digging a little deeper, I see that the function 
CyU3PDmaMultiChannelCommitBuffer returns 71 (CY_U3P_ERROR_INVALID_SEQUENCE) around the time where the issues begin.

Do you have an idea as to what might have gone wrong with the DMA, and how I should handle it ?

Thanks,

Roman