channel switch not always working with each voice

If I use try to apply a channel switch (pizz, trem, arco) to a staff, it doesn't always seem to work with the correct assigned voice, nor to work for all the voices on the staff.

In the (very short) attached channelSwith.mscz, the second tremolo (measure 3) doesn't get applied to the notes following (voice 2), nor the second pizz in measure 5. in measure 6, you'll hear a combination of pizz and archo in the chords. But the final archo corrects this, because it is being applied to the first voice (that was in pizz).

I notice in the mscx file, that I also have

it always appears in the first voice, with voice="0"

How can I apply channelSwitch to all notes in a staff?