@CTorp tried it without success, I don’t know why, but I don’t think either of us really followed up on it. There does need to be a path to ground so current flows through the diode, otherwise there’s no voltage drop across the diode. The downstream module might (ought to) provide such a path but a 100k to ground would guarantee it.
Also, note the same problem occurs in an ADSR with the decay — with a diode in the discharge path it can take seconds for the voltage to reach the sustain level. That’s probably not a big deal in most circumstances, but if it is the Kassutronics design handles it; a diode drop on the output wouldn’t.