Hi all.
In Vray I believe the correct way is to have the liquid model intersect the container (glass) slightly, this seems to give the incorrect result in Corona? Unless I’m mistaken.
What’s the best way to create this setup in Corona?
Fixed it now. It was in fact the material that was causing me problems. Everything working as expected now. 
it would be easy to understand for readers to help if you uploaded some image about your problem.
but anyway, your problem has been fixed. cheers!
Yup. Make the liquid part slightly intersect with the thickness of the glass model. Case closed. 