High Level Gathering doesn't work during Stormblood Levequests

Date & Time of Occurance: 01 March 2018 0242JST
Frequency: Always
World name: Brynhildr
Character name: Viertes Oscurita
Class/Level: 60+ (currently 66) Solo
In-game time: Always
Area and coordinates:
Steps:
1. Get the Fieldkeep main and off hand tools (tested with Fieldkeep and Doman tools)
2. Take up the Pining levequest (or any Piety-type levequests)
3. Make sure your stats are higher than the stats specified by location effect

https://i.imgur.com/jrwTR28.png

As you can see, my gathering stats is over 800 but doesn't activate the improved high-level gathering rate which required 714 gathering stat

Since the only available items to gather are equal/lower level than you, neither of them qualify as "High Level Item" so the bonus won't apply. If you were to attempt the same leve below level 63 (possibly a few levels below), you would find the bonus applied to both items. At 63, you would find it only applied to the level 66 item.