Pitcher - backward set position

[eureka25]

I have a question around ruling on a pitcher coming to a set position. Here is the situation... We have a R1 and a RH pitcher. Pitcher is straddling the rubber. He takes his pivot foot and engages the rubber as he simultaneously comes to his set position. He is set for one second and then delivers his pitch to the plate.

I see it this way and need help...I see in OBR that the pitcher must take his signs from being on the rubber. So now the argument comes is that there are no signs - no infraction(?). What rule am I missing here, because I see this as a definite occurrence of deceiving the runner/batter. It must be a balk. OBR help please.

Thanks,
Jeff