I wind my own on the bobbin winder that came with my Innova. I found if I don't have the thread going thru the disks, the bobbin will be squishy as you call it. If that happens I just put that bobbin where the spool would go and re-wind it onto another bobbin. Bobbins can go bad on you if you let them fall to the floor as they can get out of round. Test them from time to time by rolling them on a even and/or level table to see if the roll smoothly. The rattling sound usually is just a sign that its just about out. I can hear mind on my quilt machine so I know its just about out and to watch for it so I can stop the machine in time. I have robotics on my machine as well as a thread break sensor when the bobbin empties or top thread breaks but I like to catch it as early as possible.