Mine is doing that too. But not pulling the top thread at all. I've threaded and retreaded. Checked bobbin. Turned off and on. Took top off to get shreds of thread. I've had it two days. Ive been working on it for about three hours. I have no idea what it could be. It's almost like the machine is embroidering with the bobbin thread. Not even pulling top thread. If I pull it though it comes out easily. Please someone help. I'm calling dealer in am but was hoping for help sooner.

First check threading. If it is done properly, then it's probably because it is dirty between the lower tension blade and the bobbin case body. Remove this blade, clean, reassemble and it shoud work.