AdiIRC

I already reported this once, but it has never been fixed.

The problem is that the parentheses is a valid character after a slash in that position. It's only ignored if the link also starts with a parentheses, invalid: (www.adiirc.com/) valid: www.adiirc.com/)

One can argue that the parentheses is rare and could be removed even if it's valid, but in my experience, some users will complain.

There might be something like an option at some point to declare invalid characters.