This is not a shitpost. I often split windows in 2 on my desktop which gives them this aspect ratio. I noticed that the snowflakes do not appear when it is in the halfed aspect ratio.
Try to disable zoomed mode (this can cause issue with animated viewports), even though I did try every possible size and dynamically changing browser's viewport ratio. Try to refresh your cache too. Could be caused by a remnant of an older cached corrupt css.
The snowflakes use a simple css.
They load and work in every aspect ratio possible.
If you really had a rendering engine issue there should be more missing CSS stuff and artefacts.