ArcGis Desktop 10.3.1 does not dissolve to a single row while version 10.3 does it.
We use .NET API but we also tested using Python. In both cases dissolve fails to do it.
Same error in all versions > 10.3
import arcpy
arcpy.env.workspace = "C:\Users\mpersson0613\OneDrive - Quest Analytics, Inc\Documents\ArcGIS\Default.gdb"
arcpy.Dissolve_management("C:/GeoStan/2019/shapefile/FL/FLzips_region.shp", "C:/GeoStan/OutputFromPython/FLDissolveFromZip",
["STATE", "STATE_FIPS"], "ID FIRST", "MULTI_PART",
"DISSOLVE_LINES")
