G0602 timing gear

[Troutcreeks]

I noticed my Shop Fox M1099 ( a longer bed g0602 equivalent ) had developed some unusual gear noise. I found the plastic timing gear pretty badly warped (concave/convex about 0.050" around the edge) and it wobbling around its axis. Fortunately I had a replacement and the noise disappeared. Any idea what would warp it?

 

[Mitch Alsup]

Any idea what would warp it?

Heat and Torque.