This entry says is is data from Suomi-NPP satellite.
https://www.arcgis.com/home/item.html?id=363c856090d7402b971d620c0126382b
This entry says it is data from the NOAA-20 satellite.
https://www.arcgis.com/home/item.html?id=c873f4c13aa54b25b01270df9358dc64
Both entries point to https://modis.arcgis.com/arcgis/rest/services/VIIRS/ImageServer
Seems like there should be two different ImageServer resources.
Thanks for sending along the observation. The content is curated and published by NASA, who also provides the item documentation.
While the same published source, they are different in that they are accessing different imagery. When comparing the Filter between the two, note that there are differences.
I did not investigate thoroughly (and others may have additional insight), there are multiple satellites involved in collecting the imagery, which is compiled for publishing. More info here:
https://svs.gsfc.nasa.gov/5021
Thanks for the insight Ben.