I had a similar problem when changing polarity. Select a vertical Ku channel on another satellite , it would say 'no signal'. Change to a "H" channel and all was fine. Select the "V" channel and again 'no signal'. Turn off receiver whole on the "V" channel. Turn it back on and the "V" channel would come in. Turned out the vertical voltage would settle in 'no mans land', to high to switch to vertical polarity, yet to low to switch to H polarity. (Actually both voltages were higher than spec. (19.5/16.3 IIRR)
PR mux - 3813 H 8029, Lesea - 4000 H 26400, whoops guess that wouldn't be 'it'.
Just for giggles, change your programmed polarity, make one or the other V, see what happens. (don't skew the feed 90 just yet)