I don't think it should be happening with 89 octane but it is very possible to get pinging with 87. In fact in the manual it says not to worry if you have slight pinging and only bring in to dealer if pinging is severe and occurs under most conditions. I take most conditions as under normal driving with frequent occurrence.
I had slight pinging with 87 octane all stock.
2012 Kona Blue 3.7L - 6MT - 2.73 - Reverse Sensing/Security Package - Airaid CAI - SCT Tuner w/stock tune - FRPP Sport Axleback - GT Premium Steering Wheel - JLT Oil Separator