Can't taxonomy have special characters?

I want to tag “C++” or “C# winform” et el.
But specital characters(+, #) in url are omitted when publish.
I’ve set preserveTaxonomyNames = true and used urlize in href target.

This is tag link in tag.terms.html

<a href="{{ $value.Name | urlize }}"># {{ $value.Name }}</a>

and it shows like this in html… (I wrote in markdown style for example)

[# C# winform](/tags/c/#-winform/), [# C++](/tags/c/)

The url of the “C# winform” tag is /c/#-winform/, so it just links to /c/ nevertheless Hugo did generate “c%23-winform” tag page(though “c++ page not generated”).

I’ve seen the webpage using hugo has “C++” tag, so it seems that there is the way to use special characters.
Did I do something wrong?

the source of is on github
you can find the answer there…