You can check that with a midi monitor. Anyway, I think double stop is interpreted on the Elektron gear itself, not from external midi START messages. (To be tested and confirmed).
I don’t know if ST also send this ALL SOUNDS OFF CC120 message, nor if DT still send it.
(Midi monitor)
I don’t know if ST or DT accept this message.
Octatrack sends CC123, ALL NOTES OFF, which seems more appropriate, but I’m not sure.