Yes, while I was a post-graduate student at Newcastle in the mid-1960's, two researchers in the Geophysics department constructed a pair of coupled self-exciting dynamos with - they hoped - some similarity to the circulating loops of liquid metal in the earth's core. When they ran it at a steady speed, the nett dipole which it generated was extremely unstable, rising and falling, and flipping over at intervals. Nowadays we would call it a "chaotic" system.
What's inside the core is at least four, and possibly eight, circulating cells of liquid metal where the movement of each one induces electric currents in the neighbouring ones, and those currents induce magnetic fields, whose movements induce electric currents. It's so chaotic, it's a near-miracle that there's a nett dipole moment at all, and that it's as steady as it is! Yes, for sure, its polarity has flipped many many times in the past - that's permanently recorded in certain types of rocks - and it will flip again. Maybe not for another 50,000 or 100,000 years, though.