Did you get to the bottom of this at all? I’m having the same issue. For the first 4months it was fine and now skips stitches… but I’ve realised it’s after you use the thread cutter on the machine. Sewing when the bobbin thread is up it’s fine but using the thread cutter and then that’s it skipped stitches from 4-10 skipped stitches as it can’t find to bobbin thread I assume. Is yours after using the cutter by any chance?