Oh right - that's a big 'un!
I've tried drawing up something that looks similar to your, and it gives me a nice smooth curve.
Could you send me a Module or PLN file showing the problem so I can look into it a bit deeper?
Josh Osborne - Central Innovation
HP Zbook Studio G4 - Windows 10 Pro, Intel i7 7820HQ, 32Gb RAM, Quadro M1200