I also had this happen . Mine was also in the middle of the spool. Then the other day my Singer started doin crazy things. Thread breaking and knotting up on the back side of the fabric. I changed needles , I cleaned out the bits and pieces of lint and such. Then a breakthrough. I changed thread . I had been sewing with this thread for a couple of hours, then the problem. Needless to say the thread went into the trash.