How can a single misplaced screw so massively increase a stealth aircraft's radar cross-section?
In RCS, size does not matter once you move beyond the scale of the wavelength of the radar. Therefore, the RCS of a panel with an edge length of 10 cm is (theoretically at least) the same as one of a panel with 1 m edges. The screw must be so poorly placed that it will cause a larger panel to stick out so it has no electrical contact, with the edge pointing in the right direction, then this massive increase in RCS is indeed possible.