RTX ray tracing noise visible on all maps

For a minute or two I played the a RTX map "Neon District RTX" without any problems.  It suddenly showed me all the ray tracing noise as I played.  I quit the map and loaded another, this time "Imagination Island RTX" but it had the same problem as soon as it loaded.  I have taken a screenshot to show it.  I have an Nvidia RTX 2080 with the latest Nvida drivers 445.87