Gave it a short repro on Cubasis 1.9.8 / iPad Pro / iOS 9.2.1.
So far the issue seems not to be reproducible here.
Are there any additional steps required to reproduce the problem?
Feel free to upload a short video to DropBox or similar that demonstrates the issue and steps involved (link via PM please).
I think you’ve missed one step, you need to downgrade to an old iPad 3!
Your iPad Pro is fast enough to smooth out any performance issue that the devs have missed.