Skaald peers across the Gauntlet, and with his attention drawn to it by John, sees the Bridge held in place.
It's downright eerie.
Skaald, Sin and John all come to the same conclusion pretty quickly though - if this has been interfered with, the only way to do so would be to affect the slumbering spirit of the bridge in some way. Maybe it was roused, or fed strange essence.
It could just be an odd quirk of the Hisil of course, because sometimes things lack an overt sense of logic.