Steps to reproduce:

1. Open attached project
2. Open scene "repro"
3. Double-click "New Sprite" to move scene camera to it
4. Click "Edit Collider" and drag any of the handles on the handle on the opposite side until all handles are in the same place
5. Continue dragging and notice that collider slightly drifts

Reproduced with: 5.6.0b3
Not reproducible: 5.5.0p3 (because of different functionality)