https://techcrunch.com/2017/11/09/apple-just-pushed-an-ios-update-to-fix-that-i-autocorrect-bug/

Over the last few days, most iOS users have experienced the same peculiar bug: the letter “i” was autocorrecting to… something else. Sometimes it was an exclamation mark. Sometimes it was “A”. Sometimes it was a question mark in a box.

A fix was said to be just around the corner, and sure enough: Apple has just sent out a patch that fixes that rando-replacement once and for all. iOS 11.1.1 is now available, with this fix marked as the flagship feature.