No Midi, tx for asking. I'm using a Boogie MarkV: 25 with a simple TRS cable (circuit open/circuit closed).
Exact problem rgx420 describes. No option to set "tip off, ring off" or 0+0 as an instant command.
Helix will only switch to that state when you switch into a new preset, Otherwise you can't control it using an instant command.
Assigning a dedicated foot switch works fine, but blocks out those foot switches for every preset and snapshot you need them.