I've received this response:
Originally Posted by Meridian tech support
Sorry, I have just been advised that we are aware of a current issue with some hardware running Yosemite OS and Control:Mac. The issue you describe falls under this but unfortunately I do not have a set date for the fix at this time.
Hopefully there will be a software update soon that will fix it.

Control:15, TwinStore 2GB*2, 500, Auralic Vega, Pass XA60.8 x2, B&W 802D, Stax lambda & SRM-T1S, Prime Headphone Amp., HiFiMan 500