The noclip bug can occur whenever the player crosses a tagged linedef (e.g. a teleporter, a trap which opens or closes a door, or a trigger for a lift) while moving at a very high speed (such as Strafe50, or through Wallrunning). The player moves fast enough that the game engine never detects the line trigger as having been crossed.
This should not be confused with a separate bug which causes W1 linedefs to fail activation due to their target sector being busy when crossed. See Single-use line actions can fail for information on that phenomenon.