Basically, it's where differences in spelling, such as letters chosen or diacritics used, are treated as different queries by the Stack Exchange search engine, even if the queries are otherwise identical.
These concerns have previously been addressed through this post and this post, though it seems to have been buried amongst the junkyard of older, forgotten posts. I commented back in July asking if the issue has been addressed any further, but the fact that no one has responded since even then just serves to back up how I've stated it's gotten lost amongst the old posts. Or at least it has seemed to.
So, I'm wondering this: has this shortcoming been addressed? And if so, in what way(s)?