Cubasis. problems with midi clock

I’m having problems with midi clock that’s being sent out to my Yamaha Montage. I’m using CUBASIS (latest version) on my ipad and completely randomly the tempo on my Montage wil go up/down by 1 step but the CUBASIS clock/tempo is set and stays constant. This is causing me real problems with timing and is an absolute pain! I’ve recorded a short video that I can send if this helps showed the problem

Hi @Jon_Scott

Please upload the video via WeTransfer, Dropbox or similar and let me have the download link via PM.

Thanks
Lars