I used to have pitch problems after playback, with some Reaktor patches.
FINALLY figured out that for some reason, some of their factory patches had pitch tied to the mod wheel, and Sonar has a default option set ON, if I recall, to where Sonar will set all pedals and wheels and such back to ZERO when playback stops. So, for ME, stopping playback would cause the pitch to drop.
That actually happened to me on the FIRST song of my FIRST gig with a band, for the first time I used a computerized rig for live performance. So, I cannot figure out why my pitch has changed, and the singer utters the following "Just keep playing - he'll catch up".
Anyways, look for that option, and try removing the check from that option so that Sonar stops resetting all controller pedals and wheels to zero when playback stops, and see if that helps. (Preferences>Project>Midi - Zero Controllers When Play Stops).
Bob Bone