by hoover2701
Text on "Northern Tracker":"After Northern Tracker commits to a quest, place 1 progress token on each location in the staging area."
Text from Rulebook:
"If a location ever has as many progress tokens as it has quest points, that location is considered explored and is discarded from play."
As the commitment to the quest by the "Northern Tracker" is Step 1 of Questing and the Quest Resolution is Step 3 you were absolutely right in removing them beforehand.
Cheers!