The iOS 26.4 update that Apple plans to release as soon as next week includes improvements for the built-in iOS keyboard. In its notes for the software, Apple says iOS 26.4 offers "improved keyboard accuracy when typing quickly". There was a bug in iOS that caused some characters to be missed when a user was typing quickly. The character appeared to be tapped in the keyboard, but was ultimately not inserted.
The apple keyboard already changes hotbox size based on what word it thinks you want to type. Maybe someone added a 0