I ran for 2 months with a 12t titan and never had any issues. I put in a old 8.5 turn brushless and went through 3 gears in 2 days. The stock slipper wobbles the spur bad and you have to be so careful to align it correctly. That being said I was careful and still shredded the gears. I have heard that the optional lightweight slipper stops the wobble as it has a different design and and is much easier to change spur gears.http://www.amainhobbies.com/product_...er-Carrier-Set

The tendency for the gears to wobble is the only thing I can think of cause like you my mesh was perfect was not over geared maybe the extra power is causing the spur to flex or twist under the slipper.