Question Depth Mask Working in Isometric View but not in Perspective View..? (2020.2)

As title says, and seen in screenshot below, my -really standard- depth mask shader is working properly in Isometric View, but cease to work in Perspective View (both for the scene view AND the game camera). I am not using particular render pipeline or fancy graphics stuff; just straight out-of-the-box Unity 2020.2

I am currently using 2020.2.3f1, and everything worked perfectly fine when I tested in 2019.4.0f1

What could be causing the issue to appear only in 2020? Is there a specific graphics setting I should turn off?


Isometric Scene View:


Perspective Scene View:


Depth mask shader:

Code (CSharp):

1. Shader "Custom/DepthMask"
2. {
3.     SubShader
4.     {
5.         //Render the mask after regular geometry, but before masked geometry and transparent stuff
6.         Tags { "Queue"="Geometry+1" }
7.        
8.         //Don't draw in the RGBA channels
9.         ColorMask 0
10.         ZWrite On
11.  
12.         //Do nothing in pass
13.         Pass {}
14.  
15.     }
16. }