Weird indeed. If you look at the underlying code, the little box icon used to indicate an incorrect guess, in my case the square is black and links to this image file:
https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/2b1b.png
While it appears everyone else's missed box points to a white image file:
https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/2b1c.png
This obviously requires some kind of urgent comprehensive investigation! Perhaps a rotating panel of the most experienced mods here working together with teams of cyber sleuths from various countries around the world! Maybe even get the FBI... and the NSA working on it!!
Or... alternately we can just check if off as "one of those weird things".