The pixels are cracks between 16x16x16 sections. The cracks can hardly be seen before but became much worse since 1.13.
I tweaked the settings for my NVIDIA GeForce 940MX, but I still can't get the Obsidian Test absolutely correct. Did anyone manage to fix it?
Confirmed for 1.16.1.
It's noticeable that the flickering pixels aren't white. Their colors are probably the color of the sky.