“and thus is still called vinnana and vinnanakkhandha (it is understood that for an Arahant those are undefiled).”
If that is the case then there are many instances at this site that seem to make that point unclear.
Citta, Manō, Viññāna – Stages of a Thought
“I cringe when I see some online comments even say viññāna is Nibbāna. It is exactly the opposite: One attains Nibbāna when one gets rid of viññāna, or more precisely when one purifies one’s mind to the extent that a thought does not contaminate to the viññāna stage. “