How to reproduce:
1. Open the attached project "uiRepro"
2. Open the scene "SampleScene" (Assets/Scenes/SampleScene.unity)
3. Open the Game view window (Window > General > Game)
4. Observe the edges of the visible Image
5. In the Hierarchy window, select the GameObject "Main Camera"
6. In the Inspector window, change the Camera component's Projection property to "Orthographic"
7. In the Game View, observe the edges of the visible Image

Expected result: The edges remain a solid white color
Actual result: The edges have a 2px softness applied

Reproducible with: 2019.4.12f1, 2019.4.33f1, 2020.3.24f1, 2021.2.5f1, 2022.1.0b1
Not reproducible with: 2019.4.11f1

Note: Also reproducible with a Perspective Camera when the UI Canvas Render Mode is set to "Screen Space - Overlay"