It is better to put at least part of you code here if it is not for secruity reason.
Suggestion: every time after you read the serial port, add one more function to clear the port, LV VISA provides such function. Then see if the problem is still there. Or everytime, before you read the serial port, make sure you read all information in port. Also, check the hardware, not sure what kind of wireless transfer hardware you used. cannot say anything.
As for buffer and time racing, this need debug you software design.
