Omnisphere 2 - Modulation Wheel

Hi Guys,

When I use Omnisphere 2 all of a sudden it sounds out of tune, like something it pulling the modulation wheel down slightly. This happens as soon as I touch any of the midi controls (except the usual keyboard note keys).

It turns back to normal if I go to VST Instruments and turn the instrument off then back on again.

As soon as I try to control anything such as the modulation wheel it goes out of tune again and stays that way.

Can anyone help me please?