Steps to reproduce:
1. Open the attached project
2. Open the "ColliderToMesh" Scene from "Assets" > "Example" folder in the Project window

Expected results: the Mesh on "look here" GameObject contains a gap
Actual result: the Mesh on "look here" GameObject does not contain a gap

Reproducible with: 2018.4.34f1, 2019.4.25f1, 2020.3.6f1, 2021.2.0a15

Note: for reference: Scene "unCollider" contains the mesh generated using the same path as provided to PolygonCollider2D.CreateMesh, this mesh contains no gap