In rapier < 0.17.x, while doing a collider.contactCollider() check between a dynamic ball and a fixed trimesh collider, the distance value returned would be of similar value regardless of where on the trimesh contact occured. A low value of around -0.001.
In rapier 0.18.x the value returned is different depending on where the contact on the trimesh occurs. It can differ between no contact (where there is) to -0.6 on the same collider as used in 0.17.x test.