Everyone looked upwards at the countless cursed weapons descending from the formation that popped out of nowhere, their numbers kept increasing without a sing of stopping, at least until the formation showed signs of distortion.
There are quite a few reasons that could make a spatial type formation to distort, a fierce energy radiation is the most common as it basically interferes with the runes used for spatial transportation, that is why portals and space gates are always custodied by strong cultivators.
Of course, it's not like one can just release spirit energy and interfere with a spatial formation, you'll have to find the right frequency to do that and that is normally only known by the rune master who created the formation and the one who is in charge of the force or family using it.