Hi - Were you able to get this issue resolved?
I think I’m having the same problem as I just got a Nortek USB Zwave adapter for my HA system.
I have the same switch and I can connect to and HA creates this entity:
switch.leviton_dzs15_1lz_switch_switch
however, the toggles don’t appear to be working properly for me. I created this post with details:
but sounds like it might be similar to yours.
Any luck with the DZS15-1LZ Switch you were using with HA?
Thanks