Did the ecosystem instances move or did the artifact change position? From the images it's not clear. If the instances moved, it could happen if the bump is converted to displacement and you ticked the box "move ecosystem instances". Could this be your case? Did you change something in the texture in the meantime, even if it was only change the displacement quality boost?

As to the artifacts, I never experienced those but from what I could read the advice I can give is to increase the quality boost and/or the number of samples of texture anti-aliasing.

But... just one question: did you try to render without texture anti-aliasing? What's the outcome? I ask this because I actually never came upon a situation where I needed to use it so I wonder why that would be necessary in your image.