Step Input issue

Hi folks...i have a very annoying problem...many times...while using a multi timbral instrument....on one of those hybrid aux midi channels that i have routed to kontakt....step input does not work via my midi keyboard....it works on the on screen step input keyboard...but not through my external midi keyboard ...i've made sure the midi in option is selected...anyone else faced with the same problem....seems to be a glitch and its really getting in the way of my workflow especially when doing harp arpeggios while scoring