If you have a nonlinear or otherwise difficult load, it can kick in while running that. I was setting up an improvised shaker table with a seat shaker transducer (bolts to a home theater chair so you can feel the bass more) a class D amplifier reference eval kit from international rectifier we had laying around, and 2 power supplies, one for +25 V, one for -25 V.
When we hit resonance, the transducer became a very reactive load, and the output mosfets sent the current back into the supply rails, voltage shot up, and tripped the OVP at 33v, and it shut down before things started to fry. There wasn't much in the way of big bulk capacitance, just a few thousand uf on the eval kit.
A few power resistors on the rails as a static load, and the quick and dirty shaker was working again.