Never happened. There was a good deal of switching around but as of testing today, Gold Ore mines exactly three times as fast as other ores. (Testing done with 4.0 bonuses, one mining laser, sample size 300 rocks - standard rate ~10u/r, Gold ore ~30u/r)
In addition, the price at New Berlin appears to be miscalculated. Regular routes +8 min mining time are at ~700 c/s, Gold Ore to new Berlin is 643, well outside normal margin of error. Current price is 9 295; should be around 10 120 to match standard rates.