at present there is no way to configure softcut such that this exact method would produce this type of artifact. the artifact basically arises from the fact that the Phasor+BufWr combination implements a zero-order interpolation of the input signal into the buffer. softcut always performs third-order (Hermite) interpolation. at present there are no runtime options to select 1st or 0th order, but they could be pretty easily added. i think with the option of 0th order resampling, a similar effect would be easily obtained.
of course in addition to softcut norns is designed to run your own supercollider code, and certainly the linked demo will work on norns as will infinite other variants of truncation, rounding and resampling.
silly interface but quite good tools of mutilation:)