Using pitchbend wheel silences output

I suspect that this has to do with MIDI and CC's, but I have virtually no working knowledge of these things (I use only one external MIDI controller, and I don't need any elaborate settings changes). So if you care to respond to this, keep in mind my very limited knowledge.

While exploring the gobs of patches available in various instruments (seems like it was Atmospheres in Sculpture), I've found that moving the pitchwheel sometimes kills the audio output for that track via both the external and the Caps Lock keyboard (and, IF I recall correcly, leaves the Transport showing no MIDI in/out). I can still select another track and get output from its instrument via the external controller or Caps Lock, but not the initial one. To get it sounding again, I have to shut the .lso and reopen it.

In context, the most complex (ha) task I've accomplished is using Automation Quick Access to control some parameters, but I don't recall assigning them to Pitchwheel, usually just the Mod. This may not have anything to do with it; I mention it mainly to make clear that this is about the the only function I -DO- know how to use.

So as this SEEMS like some sort of command that I've inadvertently sent, I've tried finding out more by reading pp. 647-649 in the Reference. If anything there did apply to this, I simply couldn't grasp it.

I'd appreciate it if anyone's willing to explain how using the pitchwheel would shut down output for a patch, such that I have to close and reopen the file to get the track sounding again, and what preference or other control I can use to prevent it.

Thanks,
c