Lady Nun

My work for Artstation challenge "Medieval: Back and Forth"
You can find more about process here https://www.artstation.com/challenges/medieval-back-and-forth/categories/174/submissions/79411
I want to thank you again for the concept 康 (https://www.artstation.com/aass1)
And I also want to ask for help. I rendered this work in Maya Vray. My final renders have just disgusting stripes in the background. I couldn't beat them. The final render in Vray viewport was perfect, but when I save the images and open in PS, the background on the screenshot messes up. I tried saving in different formats, 8\16\32 bits, but no. I would really appreciate it if someone could help me with advice on how to deal with this.