Reading and Writing and Erasing

We just bought Explode the Code for K. She has been reading 3-letter words for almost a year, but we haven't had the 'aha' moment when it all gets easy. I attribute this to our too-early start.
At any rate, with a sudden surge in busy-ness, and now that she will be  6 (tomorrow) , I decided to buy ETC. She really likes it, so far.
Except... today she erased and rewrote the letter 'a' for about 10 minutes before I realized what she was doing. "It doesn't look right." she explained.