Is there a bug for the Kraken V3 mic mute button or has the intended use changed recently?

For a year or so I have been using my Kraken V3 (as an output) alongside a Seiren Mini (input) as my set-up.  During this time I have had almost no issues with it.  a few weeks ago I got the prompt to upgrade to Synapse 4, which I did and imported all my profiles, all in all fairly efficient - however after doing so I discovered that the mic mute button on the headset was no longer muting my mic (despite using a separate microphone this button has worked and muted my microphone input fine for the last year).  I uninstalled Synapse 4 and reinstalled 3 and that fixed the issue.  However yesterday the issue was displaying in Synapse 3 aswell.  

Is this a functionality that has been written out? Is it a bug somewhere that wiill be fixed in time?  Already missing the ability to mute myself in a call without having to bind a mute button in all the different call softwares.