Earth's magnetic field can indeed undergo rapid reversals and intervals of high instability, as evidenced by paleomagnetic records of geomagnetic excursions and polarity transitions, though some extreme local records remain debated.
Multiple papers (e.g., [0], [1], [9]) document rapid geomagnetic variability, polarity reversals, and field collapses throughout Earth's history, supporting the claim. At the same time, papers like [4] and [7] caution that some purported rapid directional changes might be local artifacts or remagnetization rather than global rapid reversals. Because the physical capacity for rapid reversals is well-established by broad paleomagnetic data while certain extreme rates are contested, the evidence supports the general claim of rapid reversals while acknowledging the nuances of specific local measurements.