Fast IP and fast socket

Hi,I use fast Ip functions to receive UDP packets, and it works well. However I bind a socket before to the same port to send request messages. But it seems to make bug the digi after some hours of normal working, and it doesn’t respond any more. Moreover this bug come more quickly when I use fast socket to send request. Did anyone use the fast IP and encountered this issue? Are the fast socket not allowed at the same time than the fast-IP ? Thanks Paul