Deep,

That part is a shock bumper. You probably have already looked at the other shock for damage to that bumper as well ti verify. Part of our quality control process is to test samples up to and including the yield point. In this case, bumpers will split down the side when crushed to their limit.

Others have suggested that you tighten up compression, which is the correct adjustment. (It's ok to even go full tight if needed to land smoothly) Even though the car didn't land hard, the bumper gave of itself to prevent that. Bumpers are not too expensive. They cost $7.07 each. Feel free to contact me if you don't have an AFCO dealer to order them from. I can be reached at eesaffell@afcoracing.com.

Eric