Water rises and then goes down as the capacitor is switched on and off:

Rise in level of liquid dielectric in capacitance https://www.youtube.com/watch?v=uHNmzcYp6JE&t=358s

Clearly, the system can do mechanical work by regularly lifting floating weights. The work will be done at the expense of ambient heat (not at the expense of electric energy), in violation of the second law of thermodynamics.

Pentcho Valev