Quote - Looks like the mesh folds and is intersecting with its own folds.
Try lower resolution mesh, and put folds in a sisplacement map.

When a cloth sim makes the mesh intersect with itself the only way out is to stiffen the cloth (reducing the folding) or go lower res mesh and with a displacement map.

Exactly. I've just gone through this same issue with a person on another board. Simply lower the poly count and the "cracks" will go away.