If i use the Displacement Input for a material then it is easy to see that it is not filtered or maybe only in one direction giving viewable pixel rendering artifacts. I appended a screenshot to illustrate the issue.
I appended a simple file that illustrates the issue together with the bump map (exr file in same directory) to illustrate the issue. I also did some other stuff in this file to circumvent the issue, but that is deactivated at the moment. It's just a simple material with an bump map texture with UV mapping.
It's due to our poor texture filtering algorithm, we don't do anything like EWA texture filtering yet, and it can indeed look quite bad with bump mapping. It's on the todo list to improve this, but for now not considered a bug.