Per discussion here, apparently this has been an issue since October 2015, if not earlier.
First of all, let me distinguish two kinds of shortcut:
- those intended to redirect to an article. Example: WP:N.
- those intended to redirect to an anchor within an article, e.g. to a heading within the article. Example: WP:GNG.
Such breakage is especially unhelpful in the case of Wikipedia guidelines. It is common practice for Wikipedia editors to use such shortcuts to refer to Wikipedia guidelines. This works very well if the shortcuts work, but if the shortcuts don't work, then it leaves the user confused about the editor's intended meaning, and about which aspects of the guidelines the editor was trying to draw to their attention.