Can't use square brackets in annotations

Annotation edit help says :

«  Because square brackets [] are used to create hyperlinks, you have to use the encoded html equivalents ([ for [") and (] for ]) if you want them not be converted into hyperlinks. Example: If you want to use [unknown] in the annotation, you'll have to write [unknown] then it will appear the way you intended it to show.  »

But all those [, [, ] and ] are converted to links.
I had to use ［fullwidth square brackets］ in the end.