I’ve encountered it before, and it was as if it started when I next opened the project. However, I may have simply not seen it while working on the project before the next time I opened it. One reference I’ve seen in the docs is it being somehow caused by a low Shadow Bias. But in the project I encountered it, I had not changed Shadow Bias from the default of 0.5…I don’t have the project now, and it was 4.23. I don’t see how it could be Shadow Bias in yours since it is appearing all over surfaces of actors. What is the lighting in the scene? Is cascaded shadow mapping on?