Setting sound volume=0 does not work correctly online with Pavlovia

with psychopy v2022.1.3 (our standardised version for the academic year)
setting volume = 0 works fine locally for psychopy experiments but the tone is still audible online with pavlovia.

The log file details the volume as null instead of 0
‘Sound2: volume = null’
and the tone is quiet though audible.
I have tried this with both PTB and sounddevice set as teh audio driver.

Any suggestions. The volume is set using a variable that is set in a custom code block ahead of the audio component in the routine.