Thanks for the reply.
The issue occurs even if I'm not using the polybrute as an external instrument in Logic, either MIDI or VST. I'm technically using the Polybrute only as a controller to trigger virtual instruments in this scenario, and those are the tracks that I'm getting constant MSB/LSB transmission.
As an example, I call up a blank session in Logic, and only create 1 track which contains Logic's "Sampler" instrument. If I record on this channel from the Polybrute, using it only as a controller, everything records as expected... but as soon as I open an instance of Connect on any other track in the session, and then I try and record on the "Sampler" channel again, I now get the stream of MSB/LSB in the recorded MIDI material. If I then remove the instance of Connect, it goes away and works as expected again.
Hopefully i'm explaining that correctly.