Hi,
We have improved the tessellation of the 2.5d displacement in the latest v7 daily build. This should resolve a lot of the artifacts which were present when using the 2.5d displacement.
You can download it here:
https://forum.corona-renderer.com/ Corona Renderer 7 for 3ds Max - Daily Builds Changelog #msg182287
I look forward to your feedback.
@Tanakov I checked this with your scene: Tanakov scene displacement fix | Corona Renderer It looks much better now 
Rowan