Just had a play..... looks to me like helix is ignoring the cc 69 value (snapshot) when forced to a program changed by bandhelper , it just happens to change to whatever snapshot was saved with the preset.....A puzzle indeed .... BP
it was indeed the position of the CC change in the Midi Preset Order sent by band helpermoving it from 2nd to 4th fixed it - PC 1st CC Last as Garethia had done....how odd !