jim137
RPN Pitch Bend Sensitivity 1535
This is the standard way on most synths to change the range of pitch bends from the default 2 semi times to 12 semi tones. That's what the 1535 value does. That is why all your pitch bends sound wrong - This midi is written to sound good with the pitch bend range set to an octave (12 semi tones).
Sadly, some of Cakewalk's synths stop making sounds when they encounter RPN events. As mentioned an other answers, you have to change the pitch bend range in the patch itself to +12 to have the pitch bends sounding correctly. Also, set the plug in to NOT intercept NRPN and RPN events.