After stitching for about an inch - maybe less - the top thread broke. And this is what I found in the bobbin case. Eeeeew!
I've run through the possibles - inserted in the case wrong - bobbin case not completely locked in - incorrect threading - etcetera, etcetera, etcetera. I can't say that none of those occurred. In fact, I believe I've pulled about every dumb operator error stunt ever invented - and invented some new ones! But none has created a tangle quite like this.
I'm saving this for my Bernina technician. She's off getting trained this week I think, but I'll stop by the shop later and see what she has to say.
BTW, after a nice cleaning and complete re-thread (and new bobbin), the sewing machine is working like a dream. Scared me for awhile, though!