It is easy to imagine what a moving object using electrical connections feels when passing through a strong magnetic field, The fan is moving faster with more amps so shows it more but any material that can transmit electrons will be perturbed some.
if you can loosely hold a screwdriver at a location the head might pass and can feel the pull then it is too much.
Better to make bed pins and hold things down that way. If you need to hold down an area you can hold down some scrap that covers the area needed.