Short answer: it is highly likely to be okay for small magnets.
A large static magnetic field can lead to saturation of inductors and transformers. When this happens, they lose their ability to store energy in the variable magnetic field. So putting a big magnet on an inductor can disrupt the circuit.
In your case, small magnets to the edge holding a filter are just not strong enough to put any meaningful magnetic flux into the any inductors inside the unit.
Mike C.