Subtank refill is a natural occurrence and isn't a problem unless it gets stuck on that screen. Every once in a while the machine needs to refill the tank when it gets too low. If something fails it generally gives you a subtank error. Turn the machine on and allow the machine to fill the subtank naturally for about 10 - 15 minutes. If it is still filling after 15 minutes, you most likely have a clog in the valve or it is malfunctioning. If you are using a bulk system and it is failing to supply ink properly, that will cause the issue as well.