PO-12 sync

Question about PO-12 sync.

I am sending PO-12 pulses from modular: triggers and gates etc. PO-12 seems to handle the voltage ranges quite well, but I noticed that, every rising edge coming into PO-12 advances it by two steps, instead of what I would expect to be just a sngle step forward.

Am curious if others see this with their setups. is this how it works when multiple PO devices are chained? Is it just modular signals that cause it? Or maybe something else?
Anyway: it would be good to hear what reliable sync scenarios you guys are utilizing.

Yes the POs and Volcas require 8 steps per bar, so for each 1 pulse the PO will move 2 steps, be careful that you do not send more than 6v p-p in though as you could damage the PO, some Euro gear outputs upto 10v p-p so just check first to be safe.