It's possible, with a self-clocking setup as shown, to generate sand (and presumably gravel) essentially on demand, rather than waiting for it to generate gradually with random ticks as is intended. This happens even with random ticks disabled. No other mods installed.

This very superficially resembles "zero-tick" farms in older versions where bamboo and other plants could be induced to grow by spamming fast piston movements underneath them, but whether this is in any way related I have no idea.