Brent,Slightly different result on a Mac, but corrupt, nonetheless - I will send the resulting gif image direct. Using 5.11.1, it put all the bad data in a bullseye at the very bottom left of the grid. Interesting how dcgrib treats the grib bulletin - try it if you want to see what I mean.
I have documented other problems to NCEP with the GRIB1-from-GRIB2 data, and this seems to be related. Have your tried, or is there available, the GRIB2 equivalent?