Seems the problem has mostly been resolved, but it still occurs on some pages (https://www.minecraft.net/about-minecraft and https://www.minecraft.net/about-dungeons) in pt-br and zh-hans.
Still affects the latest versions (26.40 & 26.50.25).
It is probably because the game treats every character separately, so that the input method cannot delete and select more than 1 character.
Can confirm.
A screenshot of version 26.33 on Windows. This problem occurs too.
Can confirm.
Can confirm.
Sulfur spike does not appears in the creative inventory nor in the “give” command.
The way of reproducing are shown in the video below.
Can confirm.
Maybe the formula should be this:
r = sqrt (n) · 262,144 (n ∈ N+)
Can confirm on 26.60.22