Android: Strange keyboard behavior on Nexus 4

To reproduce:

1. Start "Google Suggests" example
2. Input some text, such as "test".
3. Enter a space to accept pre-edit
4. Hit backspace twice.

Text displayed will be "testtes". It looks like it has appended the previous pre-edit text to the accepted text and I am now erasing this.

If I erase all the pre-edit text so that it says "test" again, and then hit backspace once more, the bug will repeat, but minus one character. This will happen until I've backspaced through everything.