静态光源的话,你可以尝试调整模型的lightmap uv.
动态光源的话,目测是深度值精度问题,可以参看文档:Content Examples Sample Project for Unreal Engine | Unreal Engine 5.1 Documentation
也可以看看官方wiki:A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums 里面有说如何设置Shadow Bias和Shadow Filter Sharpness.