Stretching Minecraft's window size like in the image below doesn't affect the suffocation overlay when you are inside a block, making it show only in the center of the screen, and you can xray through walls by changing the window size width to something very high.

To reproduce, suffocate yourself with sand or something else, exit fullscreen if you play on fullscreen and resize the window to be wide and panoramic like in the image, and you will see that the suffocation overlay only covers the center of the screen, not full screen and you can see through blocks.

This seems to not happen with nether portal overlays.

Edit: I could reproduce this from Minecraft Infdev all the way to the current version. This bug was in the game and undiscovered for 11 YEARS!