For a simple SPDT switch, the NO/NC poles are physically distanced far enough from each other that the COM will bounce for a short time on one pole, then none as it move through the free space between them, then bounce for a short time on the other pole until it settles down.
This has the effect of toggling only the input of g2, then constant input to both gates for a short while, then toggles only on g1, then constant again as the switch settles down.