From Apple’s knowledgebase:
If you updated your iPhone, iPad, or iPod touch to iOS 11.1 and find that when you type the letter “i” it autocorrects to the letter “A” with a symbol, learn what to do.
Apple suggests creating a text replacement shortcut to swap the letter
I for the letter
i. Yeah, really. They also say that they’re going to fix this in an update soon.
This is an utterly ridiculous bug to have escaped Apple’s QA checks and beta testing amongst developers and a public pool. I understand that this seems like an overreaction to a relatively minor bug, but I wasn’t kidding when I wrote last month that input devices should always work. That goes for virtual input devices, too.