I wonder if this is actually a serendipitous bug, rather than an intentional feature? If there's a hit-test heuristic associated with the general keyboard area, then the edge keys might be passing off the key event to their logical neighbor, which happens to be physically further away.
iOS (neé iPhone) 1.0 automatically resized the logical size of keyboard "keys" based on prediction models of the word you're typing. The video describing this behavior has since been pulled, but you can read the a summary of the behavior in this 2007 article: http://reviews.cnet.com/8301-19512_7-10114943-233.html
So, given that pre-existing behavior, established in iPhone 1.0 back in 2007, do you honestly believe the iPad's split keyboard behavior is a bug?
This is a very intentional and deliberate decision that improves the keyboard's usability while at the same time maintaining its aesthetics.
I'm not suggesting that the split keyboard is a bug. I'm suggested that the behavior of ghost keys to the left and right of the split might have not been intentional.
I understand; I'm saying those ghost keys are intentional, and are a logical extension of the "logical key predictive resizing" behavior present in the keyboard since 1.0.
I'd agree it "smells" more like a bug than a feature, since there is no graphical cue that you are actually pressing a key, also, holding the key doesn't cause a popup of letter variants like the ÿ.
Do you have a new iPad (or iPhone 4S) with Dictation turned on? Try this one: Press and letter and then the microphone button quickly and repeat. Instead of interrupting your quick typing, it will register the press as a space instead.
If it only went one-way that might be plausible, but I don't see how an invisible-T on the right side and an invisible-Y on the left can be anything other than a deliberate feature.
