We are getting intermittent "Data corrupt or stale" errors on our 4287A(s). I am having a hard time understanding this error message. After every command we have a "wait_complete()" loop where we send "OPC?" and check the return for something besides '0' (zero). Can someone tell me exactly what can cause this error? Since this is intermittent I assume I have a timing issue somewhere, but it only happens in production, not on my dev box.