Razer Huntsman elite volume wheel and button not working after recent update

I've been enjoying my Razer Huntsman Elite for a few months now. Noticed there was an update to Razer Synapse yesterday so happily did so. Tried to change volume in a video call or mute and the keys did nothing.

I've done some troubleshooting today and noticed a few things, if I:

• reassign the mute button and volume scroll wheel to another function, the buttons work.
  
• reassign the volume up/down/mute functions to other keys, the volume/mute changes.
  
• reassign the mute button to "Mute All" as opposed to "Mute Volume", the button works.
  
• close all Razer software (Synapse 3.0, Cortex) the button/scroll functionality returns to normal.
  

Resetting the keyboard to factory defaults has no effect. I have not modified the key mapping or anything else at all for this to have caused a problem which makes me think it was the update. Everything I have is on the default profile apart from the Chroma Studio profile. I'm on Synapse 3.5.331.31916. Not sure how I determine the firmware version of the keyboard.
Any ideas/help?