i hadn’t known of a device sending 14bit data (except pitch bend and ignoring the a4’s data out) - but it is as discussed … for info >
http://www.blitter.com/~russtopia/MIDI/~jglatt/tech/midispec/ctllist.htm
to OP - i wouldn’t blindly discount the possibility (tho i guess you’ve checked with other gear) that the arturia is sending bogus info - the micro brute has a bewildering array of unfixed bugs for an analog synth ! intriguing that it has this on mb tho