How to reproduce:
1. Open the attached project "collider.zip"
2. Open test scene
3. Select Cube in hierarchy
4. Notice that it has many Box Collides attached
5. Click on Edit Collider in first collider and edit it in the scene view
6. Collapse that box collider
7. Click on Edit Colliderin second collider
8. Notice that collider doesn't appear in the scene view

Workaround: collapse and expand second collider, then click edit again and it will work.