Smith Kennedy Jul 10, 2019

Resolved in https://ftp.pwg.org/pub/pwg/ipp/wd/wd-ippjobprinterext3v11-20190710-5100.13.docx

Stefan Brüns May 1, 2015

printer-supply[1] = ...
colorantindex=4;colorantrole=process;colorantname=cyan;coloranttonality=128;

printer-supply[2] = ...
colorantindex=4;colorantrole=process;colorantname=magenta;coloranttonality=128;

Assuming both supplies belong to the same device, either the colorantIndex has to differ, or the colorantname has to be the same.