Counting letters is such a dull test. LLMs generally have a hard time with this question because letters are tokenized before they receive them, and they have to go through an involved reasoning process to figure it out. It's like asking a color blind person what color the street light is, and declaring him unintelligent because he sometimes gets the answer wrong.
While this seems correct, I'm sure I tried this when it was novel and observed that it could split the word into separate letters and then still count them wrong, which suggested something weird is happening internally.
I just now tried to repeat this, and it now counts the "r"'s in "strawberry" correctly (presumably enough examples of this specifically on the internet now?), but I did find it making the equivalent mistake with a German word (https://chatgpt.com/share/6859289d-f56c-8011-b253-eccd3cecee...):
But even then, having it spell the word out first, fixed it: https://chatgpt.com/share/685928bc-be58-8011-9a15-44886bb522...