My DD5 did this exact same thing at that age. I was also shocked. She now writes normally.

I have a gifted DD7, but we have not had DD5 tested yet. DD7 has always been so obviously gifted that we've just assumed DD5 is our "normal" one. However, her preschool teachers and family members tell me she is definitely not normal. I guess we'll see how she does as she starts elementary.