Serial.write stops working if not used?

Projects Programming
5 
                else {
                  FLUSH:
                  while ((Serial1.available() > 0)){
                  blank = Serial1.read();  
                  }
                  IMU_flag = false;
                  return;
                }
              }
            else {
             goto FLUSH;

Please don't do this. This is what you call "spaghetti code". You will have problems all over the place. Rewrite without using goto.