ERM Multiclock and Cubase Tempo changes


Ive been using the ERM-Multiclock to sync hardware instruments up to Cubase. It works via the ERM plugin which sends an audio pulse out to the ERM unit. Everything works fine except for one thing - if I make any adjustment to the tempo in Cubase the audio stream seems to get interrupted and the ERM unit stops recieving the clock from the plugin for a moment. It seems as though changing the tempo causes the vst to choke - even if I change the tempo by a single increment.

Is this expected behaviour or should it be possible to change the tempo in Cubase in realtime without it interrupting the audio sent from a plugin?

Just to add - I have heard back from the guys at ERM and they inform me that it should be perfectly possible to sweep the tempo or even jump in 10’s of bpm without the unit losing the signal! There must be some setting in Cubase that I am overlooking. Anyone with any ideas about why it may be crapping out at the slightest tempo change?