Over the weekend, a steadily growing number of iPhone users were reporting a bug where they’d type the letter “i”, but iOS would autocorrect it to “A” plus a strange symbol (a “?” in a box).

Contrary to some rumors, this behavior is not spreading from phone to phone, or via Twitter. It is limited to iOS 11.1 and any spread is due to updates to iOS 11.1 and spread of awareness.

Note that not everyone running iOS 11.1 sees this and it is not clear what triggers this behavior.

Apple posted this knowledge base article suggesting you do a text replacement for the letter “i”. Obviously, that’s a temporary workaround until Apple releases a patch, which should be soon.

As to the cause, here’s Jeremy Burge from Emojipedia:

What’s really going on is that the letter “I” is being appended with an invisible character known as Variation Selector 16 when auto-correct kicks in to replace the lowercase “i”.

This VS-16 character is intended to be used to make the previous character have emoji appearance.[1] When used in conjunction with the letter “I” it displays in some apps as “A ⍰”.

The correct behaviour should be to ignore the invisible variation selector if the previous character doesn’t have an emoji version.

Here’s more detail on Variation Selector 16.

This will all be a bad (fond?) memory in a few days, when Apple ships their patch and it quickly makes its way to iPhones around the world.

UPDATE: And there’s this tweet, showing the “i” bug mutating. Is autocorrect learning?