EMSC-CSEM data shows a single beacon receiving S-like waves, the rest in P. Waveform from ds.iris.edu :
Strictly no S movement, no horizontality in the seismometers.
The test is camouflaged in an area of mountains as if it were a rift event. It’s not, there would be lots of S signals. Impossible for a nuclear bomb (or a magma chamber explosion, it’s identical) to trigger strong horizontal movements, it’s only a vertical event, but the Iranian government tried to cover it by detonating three bombs in a short timelapse to imitate the waveform of a small rift quake.