If it doesn't, it's just SPaG.
I mean, imagine all the minis Tumblr would spawn just for their collective disregard for capitalisation unless provoked...

I deal with minis quite often, considering I'm writing an OFU.
About capitalization: I think it only matters if the capitalization is important to the spelling. For example, there's a Star Trek: Voyager character named B'Elanna Torres. B'elanna is a mini, and so is b'elanna (and Belanna, for that matter). But torres is incorrect capitalization, not an actual misspelling. Also, something like DAta instead of Data is a mini.
Whether spells make minis: I'm not sure. For Trek I've been collecting misspellings of starships and gadgets and making them miniature versions of those things. So maybe spells would fall in a similar category, or have some entirely new property when misspelled or mis-capitalized (is that a word?). I think somebody suggested that the spells backfire, which is a good idea.
Hope this helps.

This might be my DS being a dumbass, but yor topic is reading out as just your username and the date to me.

Anybody else getting this, or...?

...if I remember correctly, fail entirely or backfire on the spellcaster.

What happens to cannon is entirely up to you of course, but I can see mispronounced spells wreaking havoc in the 'fic. It can also serve as a really ironic assassination technique...

...that it's mostly characters and places.

But maybe specific titles of spells could work as well.