On Feb 24, 2017, at 9:32 AM, Gary Tubb via INDOLOGY <indology@list.indology.info> wrote:

A colleague has asked about the history of the term “paṇḍita” 

Much relevant material can be found in: The Pandit. Traditional Sanskrit Scholarship in India. Festschrift Parameshvara Aithal.  (ed) Michaels, Axel. New Delhi: Manohar. South Asian Studies series.

I have contributed an article to this volume which may be considered directly relevant to your query: 
"Paṇḍita and pandits in history.”   

The second article in the same volume which indirectly explains how the uses noted so far on this thread become possible is: "The pandits from a piṇḍa-brahmāṇḍa point of view.”