This shows how manipulated the price of gold is. Several times over the past few years, on the day where there was some major fundamental news that should cause gold to skyrocket, the pre-market activity (when the market is at its thinnest and therefore easiest to manipulate) saw a huge dumping of naked short gold sales (paper gold), driving the price to below some important technical level, triggering automatic massive selling, which enables the manipulator to then swoop in and buy back cheaper to close their position.
The Gold market is 2% physical bullion and 98% paper promises - promises made by organizations that either have no gold or that hold 70 paper claims on every ounce.
The spot price is based on this fiction.
One day it won't be.